Question

The total cholesterol levels of a sample of men aged​ 35-44 are normally distributed with a mean of

two hundred and twelve

milligrams per deciliter and a standard deviation of

36.9

milligrams per deciliter.​(a) What percent of the men have a total cholesterol level less than

218

milligrams per deciliter of​ blood?​(b) If

248

men in the​ 35-44 age group are randomly​ selected, about how many would you expect to have a total cholesterol level greater than

252

milligrams per deciliter of​ blood?

​(a) The percent of the men that have a total cholesterol level less than

218

milligrams per deciliter of blood is

Answer 1

Mean = = 212

Standard deviation = = 36.9

a) We have to find P(X < 218)

For finding this probability we have to find z score.

That is we have to find P(Z < 0.16)

P(Z < 0.16) = 0.5646 ( Using z table)

Percent = 56.46%

b)

n = 248

First we have to find P(X > 252)

For finding this probability we have to find z score.

That is we have to find P(Z > 1.08)

P(Z > 1.08) = 1 - P(Z < 1.08) = 1 - 0.8608 = 0.1392

248*0.1392 = 34.52 35