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Descriptive Statistics in R
Quiz 1
In this tutorial, you will learn how to use compute a frequency distribution, a histogram, and measures of central tendency (e.g., mean) and dispersion (e.g., standard deviation).
Video 2 (Correlation)
Correlation in R
Quiz 2
In this tutorial, we learn how to run a correlation analysis using the Correlation function from the lessR package. In addition, we learn how to create a scatterplot using the ScatterPlot function from lessR to visually inspect the variables we wish to correlate. Finally, as an optional extension, we learn how to create an entire correlation matrix, as well as how to create a heatmap data visualization of our correlation matrix.
Video 3 (Simple Linear Reg)
Correlation & Simple Linear Regression in R
Quiz 3
In this tutorial, we use correlation and simple linear regression to validate a selection tool -- or in other words, assess its criterion-related validity. First, we use the alpha function from the psych package to estimate the internal consistency reliability of a Conscientiousness personality scale to decide whether we should compute an overall scale score for all of the available items. Second, we use the Correlation function from the lessR package to estimate the validity coefficient for the conscientiousness scale in relation to job performance. Third, we use the Regression function from the lessR package to run a simple linear regression and to test the validity coefficient in an alternative manner. Finally, we discuss the concept of variance explained using the R-squared.
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