Question

pulse rates (in bpm) were collected from a random sample of females who are non - smokers but do drink alcohol. the pulse rates before they exercised had a mean of 74.99 and a standard deviation of 11.1. the pulse rates after they ran in place for one minute had a mean of 126.5 and a standard deviation of 24.7. which of the following statements best compares the means? select an answer select an answer the pulse rates before they exercised had a higher average than the pulse rates after they ran in place for one minute. the pulse rates before they exercised had a lower average than the pulse rates after they ran in place for one minute. the middle of the pulse rates before they exercised was higher than the middle of the pulse rates after they ran in place for one minute. the middle of the pulse rates before they exercised was lower than the middle of the pulse rates after they ran in place for one minute. the pulse rates before they exercised were more consistent than the pulse rates after they ran in place for one minute. the pulse rates before they exercised were less consistent than the pulse rates after they ran in place for one minute.

Explanation:

Step1: Compare the means

The mean of pulse rates before exercise is \(74.99\). The mean of pulse rates after exercise is \(126.5\).
Since \(74.99<126.5\), the mean (average) of pulse - rates before exercise is lower than the mean (average) of pulse - rates after exercise.

Step2: Analyze other statements

• For the statements about the "middle": Mean is a measure of central tendency (average), not exactly the same as the "middle" (which could refer to median in some non - technical usages, but in a statistical sense, mean is a type of average). But even if we consider them as similar, since \(74.99 < 126.5\), the statement "The middle of the pulse rates before they exercised was higher than the middle of the pulse rates after they ran in place for one minute" is wrong.
• For the statements about consistency: Consistency is related to the standard deviation (a lower standard deviation means more consistency). The standard deviation before exercise is \(11.1\) and after exercise is \(24.7\). So, the pulse rates before exercise are more consistent. But the question asks about comparing the means, not the standard deviations.

Answer:

The pulse rates before they exercised had a lower average than the pulse rates after they ran in place for one minute.