Question

the accompanying data set lists diastolic blood - pressure measurements (mm hg) of females. all of the values are even numbers. construct a stemplot. identify the two values that are closest to the middle when the data are sorted in order from lowest to highest. (these values are often used to find the median.) 80 62 86 80 70 62 80 64 60 70 94 66 72 70 74 66 78 62 72 64 76 64 64

Explanation:

Step1: Determine the stems

The stems will be the tens - digit values of the data. The data values range from 60 - 94, so the stems will be 6, 7, 8, 9.

Step2: Determine the leaves

For each stem, list the corresponding units - digit values (leaves). For example, for stem 6, the leaves are 0, 2, 2, 4, 4, 4, 4, 6; for stem 7, the leaves are 0, 0, 2, 2, 4, 6, 8; for stem 8, the leaves are 0, 0, 0, 6; for stem 9, the leaf is 4.

Step3: Order the leaves

Order the leaves in ascending order for each stem.
The stemplot is:
6 | 0 2 2 4 4 4 4 6
7 | 0 0 2 2 4 6 8
8 | 0 0 0 6
9 | 4

Step4: Find the middle values

There are n = 20 data points. Since n is even, the median is the average of the $\frac{n}{2}$th and ($\frac{n}{2}+ 1$)th ordered data values. $\frac{n}{2}=10$ and $\frac{n}{2}+1 = 11$. Counting the ordered data values in the stemplot, the 10th value is 72 and the 11th value is 72.
The two values closest to the median are 72, 72.

Answer:

Stemplot:
6 | 0 2 2 4 4 4 4 6
7 | 0 0 2 2 4 6 8
8 | 0 0 0 6
9 | 4
Values closest to median: 72, 72