The tidy data set consists of the merged data from X_tran.txt and X_test.txt. It has 180 rows and 68 columns.
The description of all the columns follows:
1: subject_id - Identification of the subjects performing the activities, originally present in separate files subject_train.txt and subject_test.txt. Each subject performed all the activities.
2: activity - The labelled activity that the subject was performing. It can have one of the following values: WALKING, WALKING_UPSTAIRS, WALKING_DOWNSTAIRS, SITTING, STANDING, and LAYING. The activities (their IDs) were originally in separate files y_train.txt and y_test.txt. The mapping between the IDs and the names of the activities was in the file activity_labels.txt. There is one row with each activity for each subject.
3-68: These columns contain averaged values of measurements from the columns 1:6, 41:46, 81:86, 121:126, 161:166, 201, 202, 214, 215, 227, 228, 240, 241, 253, 254, 266:271, 294:296, 345:350, 424:429, 452:454, 503, 504, 516, 517, 529, 530, 542, 543, 563 of the original data set. These columns (of the original data set) concerned the mean and standard deviation of the measurements. The average is computed for each (subject_id, activity) pair. The names of the columns are assgined based on the file features.txt.