##1. Merges the training and the test sets to create one data set.
##2. Extracts only the measurements on the mean and standard deviation for each measurement.
##3. Uses descriptive activity names to name the activities in the data set
##4. 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.