codeBook.md

The output of the tidy dataset project is a dataframe which has 180 observations of the following 80 variables:

1. "subjectID" Person who participated in the experiment. Integer value from 1 to 30
2. "activityName" Kind of activity (WALKING, WALKING_UPSTAIRS, WALKING_DOWNSTAIRS, SITTING, STANDING, LAYING) being measured

• The variables below represent data from accelerometer and gyroscope signals and are bounded in the range of [-1,1]
• The next 3 variables measure the mean for the X,Y,Z coordinate values of the body acceleration

4. "tBodyAccMeanY"
5. "tBodyAccMeanZ"

• The next 3 variables measure the standard deviation for the X,Y,Z coordinate values of the body acceleration

6. "tBodyAccStdX"
7. "tBodyAccStdY"
8. "tBodyAccStdZ"

• The next 3 variables measure the mean for the X,Y,Z coordinate values of the gravity acceleration

9. "tGravityAccMeanX"
10. "tGravityAccMeanY"
11. "tGravityAccMeanZ"

• The next 3 variables measure the standard deviation for the X,Y,Z coordinate values of the gravity acceleration

12. "tGravityAccStdX"
13. "tGravityAccStdY"
14. "tGravityAccStdZ"

• The next 3 variables measure the mean for the X,Y,Z coordinate values of the jerk for body acceleration

15. "tBodyAccJerkMeanX"
16. "tBodyAccJerkMeanY"
17. "tBodyAccJerkMeanZ"

• The next 3 variables measure the standard deviation for the X,Y,Z coordinate values of the jerk for body acceleration

18. "tBodyAccJerkStdX"
19. "tBodyAccJerkStdY"
20. "tBodyAccJerkStdZ"

• The next 3 variables measure the mean for the X,Y,Z coordinate values of the body acceleration from gyroscope signals

21. "tBodyGyroMeanX"
22. "tBodyGyroMeanY"
23. "tBodyGyroMeanZ"

• The next 3 variables measure the standard deviation for the X,Y,Z coordinate values of the body acceleration from gyroscope signals

24. "tBodyGyroStdX"
25. "tBodyGyroStdY"
26. "tBodyGyroStdZ"

• The next 3 variables measure the mean for the X,Y,Z coordinate values of the body jerk from gyroscope signals

27. "tBodyGyroJerkMeanX"
28. "tBodyGyroJerkMeanY"
29. "tBodyGyroJerkMeanZ"

• The next 3 variables measure the standard deviation for the X,Y,Z coordinate values of the body jerk from gyroscope signals

30. "tBodyGyroJerkStdX"
31. "tBodyGyroJerkStdY"
32. "tBodyGyroJerkStdZ"

• The next 2 variables measure the mean and standard deviation for the magnitude of the body acceleration

33. "tBodyAccMagMean"
34. "tBodyAccMagStd"

• The next 2 variables measure the mean and standard deviation for the magnitude of the gravity acceleration

35. "tGravityAccMagMean"
36. "tGravityAccMagStd"

• The next 2 variables measure the mean and standard deviation for the magnitude of the body acceleration jerk

37. "tBodyAccJerkMagMean"
38. "tBodyAccJerkMagStd"

• The next 3 variable names measure the standard deviation and mean values from the gyroscope signals

40. "tBodyGyroMagStd"
41. "tBodyGyroJerkMagMean"
42. "tBodyGyroJerkMagStd"

• The following variables have similar meaning to the previous 3:42 variables, except that were obtained after applying a Fast Fourier Transform to the signals and they signify frequency domain signals

43. "fBodyAccMeanX"
44. "fBodyAccMeanY"
45. "fBodyAccMeanZ"
46. "fBodyAccStdX"
47. "fBodyAccStdY"
48. "fBodyAccStdZ"
49. "fBodyAccJerkMeanX"
50. "fBodyAccJerkMeanY"
51. "fBodyAccJerkMeanZ"
52. "fBodyAccJerkStdX"
53. "fBodyAccJerkStdY"
54. "fBodyAccJerkStdZ"
55. "fBodyGyroMeanX"
56. "fBodyGyroMeanY"
57. "fBodyGyroMeanZ"
58. "fBodyGyroStdX"
59. "fBodyGyroStdY"
60. "fBodyGyroStdZ"
61. "fBodyAccMagMean"
62. "fBodyAccMagStd"
63. "fBodyBodyAccJerkMagMean"
64. "fBodyBodyAccJerkMagStd"
65. "fBodyBodyGyroMagMean"
66. "fBodyBodyGyroMagStd"
67. "fBodyBodyGyroJerkMagMean"
68. "fBodyBodyGyroJerkMagStd