Question

Assumed that the body mass index(BMI) of all American young women follows a Normal distribution with standard deviation σ =7.5 How large a sample would be needed to estimate the mean BMI µ in this population to be within ±1 with 95% confidence?

Answer #1

Margin of Error = MOE = ±1

Let n be the sample size.

Standard deviation σ =7.5

Confidence level = 95%

Corresponding z score = 1.96 = z

We know that,

z table -

(18.12) Example 16.1 assumed that the body mass index (BMI) of
all American young women follows a Normal distribution with
standard deviation ? = 7.5.
How large a sample would be needed to estimate the mean BMI ? in
this population to within ±1 with 95% confidence?
Give your answer as a whole number.
Fill in the blank:

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