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   Diastolic
154 53
118 51
149 77
120 87
159 74
143 57
152 65
132 78
95 79
123 80

Find the means.
The mean for systolic is__ mm Hg and the mean for diastolic is__ mm Hg.
​(Type integers or decimals rounded to one decimal place as​ needed.)

Find the medians.
The median for systolic is___ mm Hg and the median for diastolic is___mm Hg.
​(Type integers or decimals rounded to one decimal place as​ needed.)

Compare the results. Choose the correct answer below.
A. The mean is lower for the diastolic​ pressure, but the median is lower for the systolic 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 systolic pressure are both lower than the mean and the median for the diastolic pressure.
D. The mean and the median for the diastolic pressure are both lower than the mean and the median for the systolic pressure.
E. The mean and median appear to be roughly the same for both types of blood pressure

Are the measures of center the best statistics to use with these​ data?
A. Since the systolic and diastolic blood pressures measure different​ characteristics, a comparison of the measures of center​ doesn't make sense.
B. Since the sample sizes are​ large, measures of the center would not be a valid way to compare the data sets.
C. Since the sample sizes are​ equal, measures of center are a valid way to compare the data sets.
D. Since the systolic and diastolic blood pressures measure different​ characteristics, only measures of the center should be used to compare the data sets.

What else might be​ better?
A. Because the data are​ matched, it would make more sense to investigate whether there is an association or correlation between the two blood pressures.
B. Because the data are​ matched, it would make more sense to investigate any outliers that do not fit the pattern of the other observations.
C. Since measures of center are​ appropriate, there would not be any better statistic to use in comparing the data sets.
D. Since measures of the center would not be​ appropriate, it would make more sense to talk about the minimum and maximum values for each data set.

Answer 1

Mean is given by

	Systolic		Dialostic
	154		53
	118		51
	149		77
	120		87
	159		74
	143		57
	152		65
	132		78
	95		79
	123		80
sum	1345		701
mean =sum/10	134.5		70.1

Mean for systolic= 134.5

Mean for dialostic =70.1

Median

For median we arrange the data in ascending order

n=10 , median will be average of 5th and 6th observation

Systolic		Dialostic
95		51
118		53
120		57
123		65
132		74
143		77
149		78
152		79
154		80
159		87

Median for systolic is 137.5

Median for diastolic is 75.5

Compare

B. The median is lower for the diastolic pressure , mean is lower for systolic pressure

Are the measure of center best statistic

A. Since the systolic and diastolic pressure measure different characteristics ,a comparison of measure of center does not make sense .

What else better ?

A. Because the data are matched ,it would be more sense to investigate whether there is a association or correlation between two blood pressures .