Introduction

First make sure you have navigated to the correct working directory and that this contains run_analysis.R. Then ensure that the data.table package (and any others that might be missing) are installed and loaded (there are commented out lines in the script that would do this).

Running the script

Run the script from RStudio by issuing the following command source("run_analysis.R") from the R Console. Parts of the script may take some time to run, but it should not be overly slow.

What the script produces

Running the script will result of the definition of several new variables and a function, as well as the creation of the two output datafiles in your working directory.

Variables defined

The script will result in definition of the following variables in the environment:

• subject_train
• X_train
• y_train
• subject_test
• X_test
• y_test
• subject_all - training + test subjects
• X_all - training + test feature data
• y_all - training + test activities
• lookup_features
• lookup_activity_labels
• lookup_act() function
• toMatch - values for regex column filtering
• matches - values for regex column filtering
• X_mean_std
• data_mean_std - the data table for the first dataset
• data_all
• mean_bygroup - the data frame for the second datset

Files created

The two files that will be created are:

• "data_mean_std.txt" - the first dataset
• "mean_bygroup.txt" - the second dataset