In the provided material, the standard deviation is described as which of the following?

• A. The mean of a group of scores
• B. The median of the scores
• C. Group score
• D. The range of scores

Answer: (C)

The main idea is that standard deviation tells you how spread out the scores are in a group. It’s a single value that captures how far, on average, individual scores fall from the group’s mean. It isn’t a single central value like the mean or the median, and it isn’t the difference between the highest and lowest scores (the range). Rather, it describes the variability within the group—a single descriptor of how much the group’s scores vary around the average.

If the standard deviation is small, most scores are close to the mean, indicating little variability. If it’s large, scores are more spread out, showing greater variability. So describing standard deviation as a group-level descriptor of dispersion makes sense: it summarizes how the group’s scores differ from one another around the average.