Question

The lengths of pregnancies in a small rural village are normally distributed with a mean of 266.1 days and a standard deviation of 13.1 days.

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

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

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

Answer 1

Solution :

Given that,

mean = = 266.1

standard deviation = = 13.1

Using Empirical rule,

a) P( - < x <   + ) = 68%

= P( 266.1 - 13.1 < x < 266.1 + 13.1 ) = 68%

= P( 253.0 < x < 279.2 ) =68%