Question 8 • Statistical Reasoning
The original nine mpg values total 213, so their mean is 213 ÷ 9, or about 23.7 mpg. Adding 40 mpg, which is above that mean, makes the mean increase. The median stays at 24 mpg: in the ordered list of ten values, the fifth and sixth values are both 24, so their average is still 24. Thus, the mean increases and the median does not change.
AI-written and checked against the verified answer.