Question

Newborn babies: A study conducted by the Center for Population Economics at the University of Chicago studied the birth weights of 746 babies born in New York. The mean weight was 3114 grams with a standard deviation of 858 grams. Assume that birth weight data are approximately bell-shaped. Estimate the number of newborns who weighed between 1398 grams and 4830 grams. Round to the nearest whole number.

The number of newborns who weighed between 1398 grams and 4830 grams is .

Answer 1

Solution :

Given that,

mean = = 1034

standard deviation = = 182

Using Empirical rule,

b) P( - 2 < x <   + 2 ) = 95%

= P( 3114 - 2 * 858 < x < 3114 + 2 * 858 ) = 95%

= P( 3114 - 1716 < x < 3114 + 1716 ) = 95%

=P( 1398 < x < 4830 ) = 95%

= 746 * 0.95 = 708.7

= 709 number of newborns