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.

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 (for question #3 Z - score is  (-1.8)) 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

5)

Sample size (n) = 100

Since we know that

The z-score at x = 305.0 is,

z = -1.8478 = -1.8

6)

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

PS: you have to refer z score table to find the final probabilities.

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