finn-l/gcd.project

Getting and Cleaning Data - course project - tidy data

By Finn L

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• This tidy dataset contains the averaged information about mean and standard deviation on all features. It is organized in a way that readers can easily pick up the data for each participant on each activity.

Variables explained:

• as described in the assignment requirements, variables named with "std" or "mean" in them are picked.

• then the data are summarised by both the participant number and activity identifier to be understandable by human.

For this repo, it is provided:

• a r script to reproduce the tidy data from original data set
• a code book to clarify the variable names
• readme.md file

For each row of the generated tidy data, it is provided:

• subject identifier(named "subject")
• activity identifier(named "activity")
• sets of measurements of mean and standard deviation on different features (note the variable names are modified to be more clear)

How the r script works:

1.read the original data sets , then modify the x.* data headers from the "features.txt" file.

2.get rid of irrelevant columns.

3.insert the subject and activity information from the corresponded subject_.txt and y_.txt files.

4.merge the two data sets for training and test.

5.label the activity names.

6.group merged data by subject and activity, then summarise the relevant information.

7.export the final tidy data to local folder as a ".txt" file.

Notes:

• For more details, please refer to the script comments.
• Personally I think the instructions are a little vague. So there is a chance that I misunderstand the assignment requirements.