CodeBook.md

title	CodeBook.md
author	Brian Gulbis
date	10/2/2016
output	github_document default

Project Description

The goal of this project is to create a script which will tidy-up data from the Human Activity Recognition database containing the recordings of 30 subjects performing activities of daily living while carrying a waist-mounted smartphone with embedded inertial sensors. The script is saved in the file run_analysis.R and outputs a text file with the tidy data named tidy_data.txt.

Study design and data processing

###Collection of the raw data The original data was obtained from a group of 30 volunteers between 19 and 48 years old. Each person performed six activities (walking, walking upstairs, walking downstairs, sitting, standing, and laying) while wearing a smartphone (the Samsung Galaxy S II) on the waist. The data was captured using its embedded accelerometer and gyroscope.

The sensor signals (accelerometer and gyroscope) were pre-processed by applying noise filters and then sampled in fixed-width sliding windows of 2.56 sec and 50% overlap (128 readings/window). The sensor acceleration signal, which has gravitational and body motion components, was separated using a Butterworth low-pass filter into body acceleration and gravity. The gravitational force is assumed to have only low frequency components, therefore a filter with 0.3 Hz cutoff frequency was used. From each window, a vector of features was obtained by calculating variables from the time and frequency domain.

A more detailed description of the study design and data collection can be found at http://archive.ics.uci.edu/ml/datasets/Human*Activity*Recognition*Using*Smartphones

The data for this project was obtained from https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip

###Notes on the original (raw) data For each record in the dataset, the following is provided:

• Triaxial (x-, y-, and z-axis) acceleration from the accelerometer and the estimated body acceleration.
• Triaxial (x-, y-, and z-axis) angular velocity from the gyroscope.
• A 561-feature vector with time and frequency domain variables.
• The activity label.
• An identifier of the subject who carried out the experiment.

The dataset is divided into two sets, train and test. The training data was generated by 70% of the volunteers and the test data came from the remaining 30% of the volunteers.

Within both the train and test data sets are three files:

• X_test.txt: Each row contains a measurement. The label for each measurement is contained in the features.txt file.
• y_test.txt: Each row identifies the activity being performed while taking the measurement, ranging from 1 to 6. The number corresponds to an activity label contained in the activity_labels.txt file.
• subject_test.txt: Each row identifies the subject who performed the activity ranging from 1 to 30.

##Creating the tidy datafile

###Guide to create the tidy data file The following steps should be taken to create the tidy data file:

1. Download the data from https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip
2. Unzip the file and extract into a folder called "UCI HAR Dataset" within the working directory of the run_analysis.R script.
3. In R, open the file run_analysis.R and source the script. This will clean the data and create the tidy dataset.

###Cleaning of the data The following steps are taken to clean the data a create the tidy data set:

1. The training and the test data sets are merged to create one data set.
2. For each measurement, the mean and standard deviation measures are extracted.
3. The activities are renamed with descriptive activity names.
4. The data set columns are labeled with descriptive variable names.
5. A tidy data set is created with the average of each variable for each activity and each subject.

For more information, please see README.md

##Description of the variables in the tidy_data.txt file The data set contained in the tidy_data.txt file uses a wide form of tidy data which contains 180 observations of 68 variables. The variables contain the average of each measurement from the original data which was a mean or standard deviation, grouped by activity and subject.

The variables in the data set are:

1. person
2. activity
3. time-body-accelerometer-mean-x-axis
4. time-body-accelerometer-mean-y-axis
5. time-body-accelerometer-mean-z-axis
6. time-body-accelerometer-standdev-x-axis
7. time-body-accelerometer-standdev-y-axis
8. time-body-accelerometer-standdev-z-axis
9. time-gravity-accelerometer-mean-x-axis
10. time-gravity-accelerometer-mean-y-axis
11. time-gravity-accelerometer-mean-z-axis
12. time-gravity-accelerometer-standdev-x-axis
13. time-gravity-accelerometer-standdev-y-axis
14. time-gravity-accelerometer-standdev-z-axis
15. time-body-accelerometer-jerk-mean-x-axis
16. time-body-accelerometer-jerk-mean-y-axis
17. time-body-accelerometer-jerk-mean-z-axis
18. time-body-accelerometer-jerk-standdev-x-axis
19. time-body-accelerometer-jerk-standdev-y-axis
20. time-body-accelerometer-jerk-standdev-z-axis
21. time-body-gyroscope-mean-x-axis
22. time-body-gyroscope-mean-y-axis
23. time-body-gyroscope-mean-z-axis
24. time-body-gyroscope-standdev-x-axis
25. time-body-gyroscope-standdev-y-axis
26. time-body-gyroscope-standdev-z-axis
27. time-body-gyroscope-jerk-mean-x-axis
28. time-body-gyroscope-jerk-mean-y-axis
29. time-body-gyroscope-jerk-mean-z-axis
30. time-body-gyroscope-jerk-standdev-x-axis
31. time-body-gyroscope-jerk-standdev-y-axis
32. time-body-gyroscope-jerk-standdev-z-axis
33. time-body-accelerometer-magnitude-mean
34. time-body-accelerometer-magnitude-standdev
35. time-gravity-accelerometer-magnitude-mean
36. time-gravity-accelerometer-magnitude-standdev
37. time-body-accelerometer-jerk-magnitude-mean
38. time-body-accelerometer-jerk-magnitude-standdev
39. time-body-gyroscope-magnitude-mean
40. time-body-gyroscope-magnitude-standdev
41. time-body-gyroscope-jerk-magnitude-mean
42. time-body-gyroscope-jerk-magnitude-standdev
43. frequency-body-accelerometer-mean-x-axis
44. frequency-body-accelerometer-mean-y-axis
45. frequency-body-accelerometer-mean-z-axis
46. frequency-body-accelerometer-standdev-x-axis
47. frequency-body-accelerometer-standdev-y-axis
48. frequency-body-accelerometer-standdev-z-axis
49. frequency-body-accelerometer-jerk-mean-x-axis
50. frequency-body-accelerometer-jerk-mean-y-axis
51. frequency-body-accelerometer-jerk-mean-z-axis
52. frequency-body-accelerometer-jerk-standdev-x-axis
53. frequency-body-accelerometer-jerk-standdev-y-axis
54. frequency-body-accelerometer-jerk-standdev-z-axis
55. frequency-body-gyroscope-mean-x-axis
56. frequency-body-gyroscope-mean-y-axis
57. frequency-body-gyroscope-mean-z-axis
58. frequency-body-gyroscope-standdev-x-axis
59. frequency-body-gyroscope-standdev-y-axis
60. frequency-body-gyroscope-standdev-z-axis
61. frequency-body-accelerometer-magnitude-mean
62. frequency-body-accelerometer-magnitude-standdev
63. frequency-body-accelerometer-jerk-magnitude-mean
64. frequency-body-accelerometer-jerk-magnitude-standdev
65. frequency-body-gyroscope-magnitude-mean
66. frequency-body-gyroscope-magnitude-standdev
67. frequency-body-gyroscope-jerk-magnitude-mean
68. frequency-body-gyroscope-jerk-magnitude-standdev

###Variable 1: person This variable contains the subject identification number.

• Class: Factor
• Levels: 30 (1 to 30)

###Variable 2: activity This variable contains the description of the activity.

• Class: Factor
• Levels: 6
  1. walking
  2. walking_upstairs
  3. walking_downstairs
  4. sitting
  5. standing
  6. laying

###Variable 3: time-body-accelerometer-mean-x-axis
This variable contains the average of the mean time domain signal from the accelerometer for the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: x-axis

###Variable 4: time-body-accelerometer-mean-y-axis
This variable contains the average of the mean time domain signal from the accelerometer for the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: y-axis

###Variable 5: time-body-accelerometer-mean-z-axis
This variable contains the average of the mean time domain signal from the accelerometer for the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: z-axis

###Variable 6: time-body-accelerometer-standdev-x-axis
This variable contains the average of the standard deviation of the time domain signal from the accelerometer for the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: x-axis

###Variable 7: time-body-accelerometer-standdev-y-axis
This variable contains the average of the standard deviation of the time domain signal from the accelerometer for the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: y-axis

###Variable 8: time-body-accelerometer-standdev-z-axis
This variable contains the average of the standard deviation of the time domain signal from the accelerometer for the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: z-axis

###Variable 9: time-gravity-accelerometer-mean-x-axis
This variable contains the average of the mean of the time domain signal from the accelerometer for the gravity acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: gravity
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: x-axis

###Variable 10: time-gravity-accelerometer-mean-y-axis
This variable contains the average of the mean of the time domain signal from the accelerometer for the gravity acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: gravity
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: y-axis

###Variable 11: time-gravity-accelerometer-mean-z-axis
This variable contains the average of the mean of the time domain signal from the accelerometer for the gravity acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: gravity
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: z-axis

###Variable 12: time-gravity-accelerometer-standdev-x-axis
This variable contains the average of the standard deviation of the time domain signal from the accelerometer for the gravity acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: gravity
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: x-axis

###Variable 13: time-gravity-accelerometer-standdev-y-axis
This variable contains the average of the standard deviation of the time domain signal from the accelerometer for the gravity acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: gravity
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: y-axis

###Variable 14: time-gravity-accelerometer-standdev-z-axis
This variable contains the average of the standard deviation of the time domain signal from the accelerometer for the gravity acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: gravity
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: z-axis

###Variable 15: time-body-accelerometer-jerk-mean-x-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the accelerometer using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: x-axis

###Variable 16: time-body-accelerometer-jerk-mean-y-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the accelerometer using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: y-axis

###Variable 17: time-body-accelerometer-jerk-mean-z-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the accelerometer using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: z-axis

###Variable 18: time-body-accelerometer-jerk-standdev-x-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the accelerometer using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: x-axis

###Variable 19: time-body-accelerometer-jerk-standdev-y-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the accelerometer using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: y-axis

###Variable 20: time-body-accelerometer-jerk-standdev-z-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the accelerometer using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: z-axis

###Variable 21: time-body-gyroscope-mean-x-axis
This variable contains the average of the mean time domain signal from the gyroscope using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: mean
  • Axis: x-axis

###Variable 22: time-body-gyroscope-mean-y-axis
This variable contains the average of the mean time domain signal from the gyroscope using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: mean
  • Axis: y-axis

###Variable 23: time-body-gyroscope-mean-z-axis
This variable contains the average of the mean time domain signal from the gyroscope using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: mean
  • Axis: z-axis

###Variable 24: time-body-gyroscope-standdev-x-axis
This variable contains the average of the standard deviation time domain signal from the gyroscope using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: standard deviation
  • Axis: x-axis

###Variable 25: time-body-gyroscope-standdev-y-axis
This variable contains the average of the standard deviation time domain signal from the gyroscope using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: standard deviation
  • Axis: y-axis

###Variable 26: time-body-gyroscope-standdev-z-axis
This variable contains the average of the standard deviation time domain signal from the gyroscope using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: standard deviation
  • Axis: z-axis

###Variable 27: time-body-gyroscope-jerk-mean-x-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the gyroscope using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: x-axis

###Variable 28: time-body-gyroscope-jerk-mean-y-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the gyroscope using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: y-axis

###Variable 29: time-body-gyroscope-jerk-mean-z-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the gyroscope using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: z-axis

###Variable 30: time-body-gyroscope-jerk-standdev-x-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the gyroscope using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: x-axis

###Variable 31: time-body-gyroscope-jerk-standdev-y-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the gyroscope using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: y-axis

###Variable 32: time-body-gyroscope-jerk-standdev-z-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the gyroscope using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: z-axis

###Variable 33: time-body-accelerometer-magnitude-mean
This variable contains the average of the mean of the magnitude signal (calculated using the Euclidean norm) for the time domain from the accelerometer using the body acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 34: time-body-accelerometer-magnitude-standdev
This variable contains the average of the standard deviation of the magnitude signal (calculated using the Euclidean norm) for the time domain from the accelerometer using the body acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal calculation: magnitude
  • Calculation: standard deviation

###Variable 35: time-gravity-accelerometer-magnitude-mean
This variable contains the average of the mean of the magnitude signal (calculated using the Euclidean norm) for the time domain from the accelerometer using the gravity acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: gravity
  • Sensor signal: accelerometer
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 36: time-gravity-accelerometer-magnitude-standdev
This variable contains the average of the standard deviation of the magnitude signal (calculated using the Euclidean norm) for the time domain from the accelerometer using the gravity acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: gravity
  • Sensor signal: accelerometer
  • Signal calculation: magnitude
  • Calculation: standard deviation

###Variable 37: time-body-accelerometer-jerk-magnitude-mean
This variable contains the average of the mean of the magnitude (calculated using the Euclidean norm) of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the accelerometer using the body acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 38: time-body-accelerometer-jerk-magnitude-standdev
This variable contains the average of the standard deviation of the magnitude (calculated using the Euclidean norm) of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the accelerometer using the body acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Signal calculation: magnitude
  • Calculation: standard deviation

###Variable 39: time-body-gyroscope-magnitude-mean
This variable contains the average of the mean of the magnitude signal (calculated using the Euclidean norm) for the time domain from the gyroscope using the body acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 40: time-body-gyroscope-magnitude-standdev
This variable contains the average of the standard deviation of the magnitude signal (calculated using the Euclidean norm) for the time domain from the gyroscope using the body acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal calculation: magnitude
  • Calculation: standard deviation

###Variable 41: time-body-gyroscope-jerk-magnitude-mean
This variable contains the average of the mean of the magnitude (calculated using the Euclidean norm) of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the gyroscope using the body acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 42: time-body-gyroscope-jerk-magnitude-standdev
This variable contains the average of the standard deviation of the magnitude (calculated using the Euclidean norm) of the Jerk signal (derived from the body linear acceleration and angular velocity) for the time domain from the gyroscope using the body acceleration signal.

• Class: numeric
• Unit of Measure: seconds
• Description of Naming Schema:
  • Signal domain: time
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Signal calculation: magnitude
  • Calculation: standard deviation

###Variable 43: frequency-body-accelerometer-mean-x-axis
This variable contains the average of the mean frequency domain signal from the accelerometer using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: x-axis

###Variable 44: frequency-body-accelerometer-mean-y-axis
This variable contains the average of the mean frequency domain signal from the accelerometer using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: y-axis

###Variable 45: frequency-body-accelerometer-mean-z-axis
This variable contains the average of the mean frequency domain signal from the accelerometer using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: mean
  • Axis: z-axis

###Variable 46: frequency-body-accelerometer-standdev-x-axis
This variable contains the average of the standard deviation frequency domain signal from the accelerometer using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: x-axis

###Variable 47: frequency-body-accelerometer-standdev-y-axis
This variable contains the average of the standard deviation frequency domain signal from the accelerometer using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: y-axis

###Variable 48: frequency-body-accelerometer-standdev-z-axis
This variable contains the average of the standard deviation frequency domain signal from the accelerometer using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Calculation: standard deviation
  • Axis: z-axis

###Variable 49: frequency-body-accelerometer-jerk-mean-x-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the accelerometer using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: x-axis

###Variable 50: frequency-body-accelerometer-jerk-mean-y-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the accelerometer using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: y-axis

###Variable 51: frequency-body-accelerometer-jerk-mean-z-axis
This variable contains the average of the mean of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the accelerometer using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: mean
  • Axis: z-axis

###Variable 52: frequency-body-accelerometer-jerk-standdev-x-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the accelerometer using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: x-axis

###Variable 53: frequency-body-accelerometer-jerk-standdev-y-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the accelerometer using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: y-axis

###Variable 54: frequency-body-accelerometer-jerk-standdev-z-axis
This variable contains the average of the standard deviation of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the accelerometer using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Calculation: standard deviation
  • Axis: z-axis

###Variable 55: frequency-body-gyroscope-mean-x-axis
This variable contains the average of the mean frequency domain signal from the gyroscope using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: mean
  • Axis: x-axis

###Variable 56: frequency-body-gyroscope-mean-y-axis
This variable contains the average of the mean frequency domain signal from the gyroscope using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: mean
  • Axis: y-axis

###Variable 57: frequency-body-gyroscope-mean-z-axis
This variable contains the average of the mean frequency domain signal from the gyroscope using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: mean
  • Axis: z-axis

###Variable 58: frequency-body-gyroscope-standdev-x-axis
This variable contains the average of the standard deviation frequency domain signal from the gyroscope using the body acceleration signal along the x-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: standard deviation
  • Axis: x-axis

###Variable 59: frequency-body-gyroscope-standdev-y-axis
This variable contains the average of the standard deviation frequency domain signal from the gyroscope using the body acceleration signal along the y-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: standard deviation
  • Axis: y-axis

###Variable 60: frequency-body-gyroscope-standdev-z-axis
This variable contains the average of the standard deviation frequency domain signal from the gyroscope using the body acceleration signal along the z-axis.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Calculation: standard deviation
  • Axis: z-axis

###Variable 61: frequency-body-accelerometer-magnitude-mean
This variable contains the average of the mean of the magnitude signal (calculated using the Euclidean norm) for the frequency domain from the accelerometer using the body acceleration signal.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 62: frequency-body-accelerometer-magnitude-standdev
This variable contains the average of the standard deviation of the magnitude signal (calculated using the Euclidean norm) for the frequency domain from the accelerometer using the body acceleration signal.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal calculation: magnitude
  • Calculation: standard deviation

###Variable 63: frequency-body-accelerometer-jerk-magnitude-mean
This variable contains the average of the mean of the magnitude (calculated using the Euclidean norm) of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the accelerometer using the body acceleration signal.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 64: frequency-body-accelerometer-jerk-magnitude-standdev This variable contains the average of the standard deviation of the magnitude (calculated using the Euclidean norm) of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the accelerometer using the body acceleration signal.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: accelerometer
  • Signal derivation: jerk
  • Signal calculation: magnitude
  • Calculation: standard deviation

###Variable 65: frequency-body-gyroscope-magnitude-mean
This variable contains the average of the mean of the magnitude signal (calculated using the Euclidean norm) for the frequency domain from the gyroscope using the body acceleration signal.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 66: frequency-body-gyroscope-magnitude-standdev
This variable contains the average of the standard deviation of the magnitude signal (calculated using the Euclidean norm) for the frequency domain from the gyroscope using the body acceleration signal.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal calculation: magnitude
  • Calculation: standard deviation

###Variable 67: frequency-body-gyroscope-jerk-magnitude-mean
This variable contains the average of the mean of the magnitude (calculated using the Euclidean norm) of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the gyroscope using the body acceleration signal.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Signal calculation: magnitude
  • Calculation: mean

###Variable 68: frequency-body-gyroscope-jerk-magnitude-standdev This variable contains the average of the standard deviation of the magnitude (calculated using the Euclidean norm) of the Jerk signal (derived from the body linear acceleration and angular velocity) for the frequency domain from the gyroscope using the body acceleration signal.

• Class: numeric
• Unit of Measure: Hz
• Description of Naming Schema:
  • Signal domain: frequency
  • Sensor acceleration signal: body
  • Sensor signal: gyroscope
  • Signal derivation: jerk
  • Signal calculation: magnitude
  • Calculation: standard deviation

##Sources A more detailed description of the study design and data collection can be found at http://archive.ics.uci.edu/ml/datasets/Human*Activity*Recognition*Using*Smartphones

The data for this project was obtained from https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip

The dplyr library was used in the script to manipulate table data.