Final answer:
In a left-skewed data set, the mean is typically less than the median due to the influence of low numbers in the tail pulling the mean downward.
Step-by-step explanation:
If the data set is skewed to the left, the typical relationship between the mean and median is that the mean is less than the median. This happens because the mean is affected more by the low numbers in the left tail of the distribution. The median, being the middle value of a data set, is not as affected by extreme values. Therefore, in a left-skewed distribution, the mean is 'pulled' toward the longer tail, resulting in a mean that is lower than the median.