What statistical measure would best represent the average score of a test with extreme low and high values affecting the result?

The median is the best measure to represent the average score of a test when there are extreme low and high values that could skew the results. The median is the middle value of a data set when it is ordered from least to greatest. This means that it effectively divides the dataset in half, ensuring that half of the scores are below the median and half are above, regardless of any outliers.

When a dataset contains extreme values, these outliers can significantly affect the mean, pulling it toward the high or low end of the scale depending on their values. In contrast, the median remains stable because it is unaffected by the actual values of the extreme scores; it only considers the position of the scores in relation to one another.

In summary, using the median in situations where there are outliers provides a more representative measure of the central tendency of the data, making it the most suitable choice in this scenario.