Project README

Mark Pauley 4/22/2021

The dataset includes the following files:

• README.md: This file

• runAnalysis.R: Contains the commented script that does the analysis. The script must be run in a directory containing features.txt, subject_train.txt, subject_test.txt, X_train.txt, X_test.txt, Y_train.txt, and Y_test.txt from the project file. The script creates the file dataSummary.csv described below.

• CodeBook.md: A file that describes the variables, data, and transformations performed to clean the data, although most of this is done below and with comments in runAnalysis.R.

• dataSummary.csv: Summary of the data, with a header row. A 181 × 68 file containing the averages of each variable for each activity and each subject.

Briefly, runAnalysis.R does the following:

• Loads the features, subjects, X, and Y files. A column (Role) is added in the subjects data frame indicating whether a given subject was used for training or testing. For the X data, the entries in features.txt are used as descriptive column names, and only the columns with “mean()” and “std()” are selected. For the Y files, activity numbers are converted to activity names.

• Merges the data frames for training and testing subjects into individual frames.

• Merges the two data frames resulting from the previous step into a single frame.

• Computes summary statistics for the combined data set, grouped by subject, activity, and role (whether the subject was used for training or testing).

• Writes the result from the previous step to a comma-delimited file, dataSummary.csv.