Question

a sample of blood pressure measurements is taken from a data set and those values (mm hg) are listed below. the values are matched so that subjects each have systolic and diastolic measurements. find the mean and median for each of the two samples and then compare the two sets of results. are the measures of center the best statistics to use with these data? what else might be better?

systolic: 114, 96, 146, 109, 121, 139, 97, 137, 117, 118
diastolic: 57, 74, 59, 56, 67, 58, 91, 69, 54, 76

find the means.
(type integers or decimals rounded to one decimal place as needed.)
the mean for systolic is 119.4 mm hg and the mean for diastolic is 66.1 mm hg.

find the medians.
(type integers or decimals rounded to one decimal place as needed.)
the median for systolic is 117.5 mm hg and the median for diastolic is 63 mm hg.

compare the results. choose the correct answer below.
a. the mean and the median for the systolic pressure are both lower than the mean and the median for the diastolic pressure.
b. the median is lower for the diastolic pressure, but the mean is lower for the systolic pressure.
c. the mean and the median for the diastolic pressure are both lower than the mean and the median for the systolic pressure.
d. the mean and median appear to be roughly the same for both types of blood pressure.
e. the mean is lower for the diastolic pressure, but the median is lower for the systolic pressure.

Explanation:

We have the mean for systolic as 119.4, median for systolic as 117.5; mean for diastolic as 66.1, median for diastolic as 63.

• Compare mean: 66.1 (diastolic) < 119.4 (systolic)
• Compare median: 63 (diastolic) < 117.5 (systolic)

So both mean and median for diastolic are lower than those for systolic. Option C says "The mean and the median for the diastolic pressure are both lower than the mean and the median for the systolic pressure" which matches.

Answer:

C. The mean and the median for the diastolic pressure are both lower than the mean and the median for the systolic pressure.