Jamie’s Intro to Biology professor tells the class that on the first exam, the mean score is a 70, but the median score is an 84. What does this tell you about the skewness of the distribution? What measures of center and spread would you use to describe this distribution? a. The distribution is skewed left, so we should use the mean and the median to describe the distribution. b. The distribution is skewed left, so we should use the median and the IQR to describe the distribution. c. The distribution is skewed right, so we should use the median and the IQR to describe the distribution. d. The distribution is symmetric, so we should use the standard deviation and the IQR to describe the distribution. e. The distribution is skewed right, so we should use the mean and the IQR to describe the distribution.

Definition Definition Middle value of a data set. The median divides a data set into two halves, and it also called the 50th percentile. The median is much less affected by outliers and skewed data than the mean. If the number of elements in a dataset is odd, then the middlemost element of the data arranged in ascending or descending order is the median. If the number of elements in the dataset is even, the average of the two central elements of the arranged data is the median of the set. For example, if a dataset has five items—12, 13, 21, 27, 31—the median is the third item in ascending order, or 21. If a dataset has six items—12, 13, 21, 27, 31, 33—the median is the average of the third (21) and fourth (27) items. It is calculated as follows: (21 + 27) / 2 = 24.