CodeBook.md

Code Book

The input data:

• train/X_train.txt;
• test/X_test.txt;
• train/subject_train.txt;
• test/subject_test.txt;
• train/y_train.txt;
• test/y_test.txt;
• features.txt contains some measurements;
• activity_lables.txt contains descriptive activity names.

The variables

X binds train/X_train.txt with test/X_test.txt.

Y binds train/y_train.txt with test/y_test.txt.

subject binds train/subject_train.txt with test/subject_test.txt.

Work to clean up the data

All feature names and activity labels are converted to lower case, while underscore and brackets are removed.

The output data

The result is saved in the tidy.txt file, a 180x68 data frame:

• the first column contains subject IDs;
• the second column contains activity names;
• the columns 3-68 contain the averages for each of the 66 attributes.

There are 30 subjects and 6 activities, generating 180 rows in this data.