What is standard deviation used for in IQ testing?

Standard deviation is a crucial statistical measure that helps researchers understand the variability of IQ scores within a population. In the context of IQ testing, it allows for the assessment of how spread out the scores are around the mean (average) IQ score. A lower standard deviation indicates that the IQ scores are clustered closely around the mean, suggesting that most individuals have similar intelligence levels. Conversely, a higher standard deviation indicates greater variability, with scores more dispersed.

Using standard deviation in IQ testing enables psychologists to identify the consistency of IQ scores across a group. This understanding is essential for interpreting the results of individual tests in relation to the larger population. For instance, if an individual’s score falls within one standard deviation of the mean, it signifies that their score is typical, while scores further away suggest more significant deviations from the average.

Thus, standard deviation serves as a valuable tool in evaluating and comparing IQ scores, providing insights into the population's intelligence distribution and highlighting the consistency of those scores.