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 have both 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? systolic: 136 145 99 100 140 134 155 122 111 151 76 66 80 65 69 58 85 51 77 54 diastolic: the mean and the median for the diastolic pressure are both lower than the mean and the median for the systolic pressure. the mean and median appear to be roughly the same for both types of blood pressure. the mean and the median for the systolic pressure are both lower than the mean and the median for the diastolic pressure. the mean is lower for the diastolic pressure, but the median is lower for the systolic pressure. are the measures of center the best statistics to use with these data? a. since the sample sizes are large, measures of center would not be a valid way to compare the data sets. b. since the sample sizes are equal, measures of center are a valid way to compare the data sets. c. since the systolic and diastolic blood - pressure measure different characteristics, only measures of center should be used to compare the data sets. d. since the systolic and diastolic blood - pressure measures different characteristics, a comparison of the measures of center doesnt make sense.

Explanation:

Step1: Recall measure - of - center concepts

The mean and median are measures of center. When comparing two data - sets, if the data have different characteristics (such as different distributions), comparing measures of center may not be meaningful. Systolic and diastolic blood pressures are different physiological measurements with different normal ranges and distributions.

Answer:

D. Since the systolic and diastolic blood pressures measure different characteristics, a comparison of the measures of center doesn't make sense.