Answer:
1 Choosing Appropriate Measures
The dot plot shows the average number of hours students in a class
sleep each night.
6 7 8 9 10
Time (hours)
Amount of Sleep
a. What are the most appropriate measures to describe the center
and the variation?
Most of the data values are on the right clustered around 9, and the
tail extends to the left. The distribution is skewed left.
So, the median and the interquartile range are the most
appropriate measures to describe the center and the variation.
b. Describe the center and the variation of the data set.
The median is 8.5 hours. The fi rst quartile is 7.5, and the third
quartile is 9. So, the interquartile range is 9 − 7.5 = 1.5 hours.
The data are centered around 8.5 hours. The middle half of the
data varies by no more than 1.5 hours.
