Getting and Cleaning Data Course Project R Script

# You should create one R script called run_analysis.R that does the following: 
# 
# 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.