The cholesterol levels in healthy individuals are approximately normally distributed. For males under 21 in a population, the average cholesterol level is 160 mg/di with a standard deviation of 15 mg/dl.

1. Identify u and a for this question.

160

mg/di; o =

15

mg/dl

2. If a male under 21 is selected at random, find the probability that his cholesterol level is above 147 mg/dl.

a) Find the Z-score (show your work using the numerical values in the formula and round the z-score to two decimal places) for 147:

117 - 160

-0.87

Z =

15

b) Sketch the corresponding region to the statement with the Z-score. Select from the dropdown menu to shade to the left, to the right, between or left and right of the Z-score(s); and then shade the corresponding region. The arrow can only drag to the Z-score that is rounded to one decimal place (these values correspond to the tick marks on the horizontal axis).

Shade: Right of a val

. Click and drag the arrows to adjust the values.

-0.9

c) Find the left-cumulative area (keep 4 decimal places) corresponding to the Z-score: