EXAMPLE 2 Finding the quartiles

Hank Aaron’s 23 home run counts are

271

There is an odd number of observations, so the median is the one in the middle, the bold 34 in the list. To find the quartiles, ignore this central observation. The first quartile is the median of the 11 observations to the left of the bold 34 in the list. That’s the sixth, so . The third quartile is the median of the 11 observations to the right of the bold 34. It is .

Barry Bonds’s 22 home run counts are

The median lies halfway between the middle pair. There are 11 observations to the left of this location. The first quartile is the median of these 11 numbers. That’s the sixth, so . The third quartile is the median of the 11 observations to the right of the overall median’s location, .