The grades on a chemistry exam for a sample of 30 students are as follows:
(a) Construct the stem and leaf plot for these data using 10's as the stems.
(b) Find the median, first quartile and the third quartile for these data.
Solution: (a) We get
(b) We have the following summary:
This means that the median is m = 68, the first quartile is Q1 = 58, and the third quartile is Q3 = 79.