Question

Sampling Distribution
Complete solutions and illustrations are required.

3.The mean systolic blood pressure of normal adults is 120 millimeters of mercury (mm Hg) and the standard deviation is 5.6. Assume that the variable is normally distributed.
a.If an individual is selected, find the probability that the individual’s pressure will be between 118 and 122 mm Hg.
b.If a sample of 35 adults is randomly selected, find the probability that the sample mean will be between 119 and 121 mm Hg.

Answer 1

a. Z = (score-mean)/SD

b. Z = (score-mean)/SEm

SEm = SD/√n

With both problems, find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to the Z scores.