NOTE: You must download and extract the dataset from UCI HAR Dataset repo containig data and its descirption before you move to the assignment part.
run_analysis.R file contains all the logic to get and clean data in order to perform analysis. Execute the script to obtain tidy data set, which will be similar to the dataset stored in tidy_dataset.csv file.
1- merge_train_test_dataset
The function returns dataset which contains observations from both train and test dataset. It first loads the training data from X_train.txt file stored in UCI HAR Dataset/train directory into a data table and binds with it subject variable as well as activity variable related to the training data, which is stored in file subject_train.txt and activity_labels.txt respectively. It then performs same steps for test data as well which is stored in directory UCI HAR Dataset/test and then merges the train and test dataset.
2- activities_transforming_into_descriptive_activities
The function apply transformation to activity variable by transforming activity values into descriptive form. The following transformation/mapping was applied:
1 was mapped to WALKING
2 was mapped to WALKING_UPSTAIRS
3 was mapped to WALKING_DOWNSTAIRS
4 was mapped to SITTING
5 was mapped to STANDING
6 was mapped to LAYING
3- extract_measurements_mean_std
The function is resposible for extracting only the measurements on the mean and standard deviation for each measurement from the dataframe returned by above function.
4- average_activity_subject
The function takes in the dataframe returned by above function and then calculates the average of each variable for each activity and each subject and returns the summary in a dataframe.