Mean: the average of all the data points; calculated by taking the sum of the data points and divdiding by the total number of data points.

Range: one way of looking at the variability in the data points, range is the difference between the highest and lowest numbers, calculated by subtracting the lowest data point from the highest data point in the set.

Standard Deviation: the degree to which each data point in the set of data points varies or deviates from the mean; caluclated by taking the square root of the sum of the deviations from the mean squared divided by the number of scores in the sample.

Coefficient of Variance: a measure of the variability of a set of data points; calculated by dividing the standard deviation by the mean.

Correlation Coefficient: the degree to which two or more different variables are related; calculated through a fairly complicated procedure relating the variables of interest.

Long & Slichter