12. Measures of Center and Spread: Mixed Practice

This session reviews Sessions 7–11 (mean, median, mode, range, weighted averages, quartiles, IQR, and standard deviation) through mixed, GED®-style practice problems.

Focus areas:

1. Calculating each measure correctly from a raw list, a frequency table, or a graph.
2. Recognizing which measure a word problem is actually asking for. GED® questions often use the everyday word "average," which always refers to the mean unless stated otherwise.
3. Choosing the best measure of center or spread to describe a given data set, and justifying that choice using skew or outliers.
4. Comparing two data sets side by side, for example two classes' test scores, using both center and spread.

We will work through a timed problem set and review common error patterns, such as forgetting to reorder data before finding the median, or confusing range with IQR.