1.Install then load stringr and dplyr packages
2.Download the file then load them into R
3.Merges the training and the test sets to create a dataset named merged
4.Extracts only the measurements on the mean and standard deviation for each measurement, to extracted_data
5.Uses descriptive activity names to name the activities in the extracted_data
6.Remove the speical symbols in the variable names
7.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, which is named tidy_data