gettingAndCleaningData_2

In what follows, the code is to described in a step-by-step fashion:

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STEP(0) Downloading the data

Downloading the data using "download.file" function. Then:

• unzip the file into folder "dataset"
• leave the unzipped folder in the working directory and
• keep the structure of the folder unchanged.

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STEP(1) Reading-in and merging data

Individual files are read-in (using read.table) and merged using cbind and rbind respectively.

Features are stored in data.frame "X", response in array "y". Data.frame "subject_ID" contains individual subjects.

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STEP(2) Extracting mean() and std() features

After feature-names are loaded in from "features.txt", only features that have "mean()" or "std()" in their names are kept in.

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STEP(3) Fetching activity labels

Library sqldf is used to left-join activity labels to the response 'y'.

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STEP(4) Labeling of features and generating the final scoringDataSet

The scoringDataSet is a composed from selected features and the response

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STEP(5) Summarizing

ScoringDataSet is grouped by subject and response and for each group and average is computed for each of the group.