Question

The lengths of pregnancies in a small rural village are normally distributed with a mean of 264 days and a standard deviation of 15 days.

In what range would you expect to find the middle 68% of most pregnancies?

Between___and___

If you were to draw samples of size 60 from this population, in what range would you expect to find the middle 68% of most averages for the lengths of pregnancies in the sample?

Between___ and ____

Enter your answers as numbers. Your answers should be accurate to 1 decimal places.

Answer 1

1)

According to the empirical rule, approximately 68%, 95% and 99.73% observations lie within one, two and three standard deviations from mean respectively.

Now,

So, the middle 68% pregnancies would lie between 234 days and 294 days.

2)

Also,

So, the middle 68% of most averages for lengths of pregnancies in the sample would lie between days and days.