Question

In a study on the physical activity of people, researchers measured overall physical activity as the total number of registered movements (counts) over a period of time and then computed the number of counts per minute (cpm) for each subject. The study revealed that the overall physical activity of obese people has a mean of μ=322cpm and a standard deviation σ=92cpm. In a random sample of 100 obese people, consider x ̅, the sample mean counts per minute.

3) What is the z-score for a sample mean of 305?

0/10 Points

• 1.8

• -0.18

• -1.7

• -0.17

5) Suppose we are interested in the activity of one individual with a cpm distribution that is approximately normal. Find the z-score of a person with 305 cpm.

0/10 Points

• -2.1

• -0.17

• -1.7

• -1.8

6) Which of the following statements best describes the difference between the answer to #3 and #5?

0/10 Points

• The z-score for the an individual is greater than that of a sample mean because the distribution for an individual is more spread out (large standard deviation).

• The z-score for the an individual is the same than that of a sample mean because they both involve 305 cpm and a normal distribution.

• The z-score for the an individual is the same than that of a sample mean because the distributions are both normal with the same mean.

• The z-score for the an individual is less than that of a sample mean because the distribution for an individual is less spread out (small standard deviation).

Answer 1

I think the options of both 3,5 are interchanged. Please check once.

6)According to the central limit theorem,the mean of the population would follow a normal distribution with the mean equal to the population mean and the SD equal to SD of population divided by root of the sample size.

Hence, here we find the "Z Score for the individual to be greater than that of the sample mean because the distribution for an individual is more spread out."