Question

The lengths of pregnancies in a small rural village are normally distributed with a mean of 261 days and a standard deviation of 17 days. In what range would you expect to find the middle 95% of most pregnancies?

Answer 1

range is between 294.32 and 227.68 expect the middle 95% of most pregnancies

Explanation:

Given data

mean μ = 261 days

standard deviation SD = 17 days

most pregnancies = 95%

to find out

In what range expect to find the middle 95% of most pregnancies

solution

we have Z value for 95% is 1.96

so Confidence interval = mean +/- 1.96×SD

put vale

Confidence interval = 261 +/- 1.96(17)

Confidence interval = 294.32 and 227.68

range is between 294.32 and 227.68 expect the middle 95% of most pregnancies