Directions Draw a clearly labeled diagram and then solve eac

Directions: Draw a clearly labeled diagram and then solve each problem.

The mean pulse rate for adults is 72 beats per minute (www.healthepic.com) and let’s suppose that the standard deviation is 10. Find:

a. The probability that a randomly chosen adult has a pulse rate over 80 assuming that the rates are normally distributed.

b. The probability that a random sample of 19 adults will have a mean score over 80.

Solution

A.

For individual scores,

z = (X - u)/sigma

Thus,

z = 0.80

which has right tailed area of

P(z > 0.80) = 0.211855 [ANSWER]

*********************

B.

For samples,

z = (X - u) * sqrt(n) /sigma

Thus,

z = 3.4871

which has a right tailed area of

P(z > 3.4871) = 0.000244 [ANSWER]

**********************