Getting and Cleaning Data Course Project

This script will do the following

1. Extracts only the measurements on the mean and standard deviation for each measurement.
2. Merges the training and the test sets to create one data set.
3. Appropriately labels the data set with descriptive variable names.
4. Uses descriptive activity names to name the activities in the data set
5. creates a second, independent tidy data set with the average of each variable for each activity and each subject and writes to a file called Tidy.txt.