The purpose of this project is to demonstrate the ability to collect, work with, and clean a data set.

1.Merges the X_training, X_test and y_train, y_test sets respectively.

2.Extracts only the measurements on the mean and standard deviation for each measurement (79 columns at this step).

3.Uses descriptive activity names to name the activities in the data set.

4.Merge the new data sets to a united one and appropriately labels the data set with descriptive variable names.

5.From the data set in step 4, creates a second, independent tidy data set with the average of each variable for each activity and each subject. Then store the tidy data set into a table named tidytable(dimension: 180 * 81).