Question

A study studied the birth weights of 2,032 babies born in the United States. The mean weight was 3234 grams with a standard deviation of 871 grams. Assume that birth weight data are approximately bell-shaped. Estimate the number of newborns who weighed between 1492 grams and 4976 grams. Write only a number as your answer. Round your answer to the nearest whole number.

Answer 1

Solution :

Given that ,

mean = = 3234

standard deviation = = 871

P(1492 < x < 4976) = P((1492 - 3234 / 871) < (x - ) / < (4976 - 3234) / 871) )

P(1492 < x < 4976) = P(-2 < z < 2)

P(1492 < x < 4976) = P(z < 2) - P(z < -2)

P(1492 < x < 4976) = 0.9772 - 0.0228 = 0.9544

Probability = 0.9544

The number of newborns who weighed between 1492 grams and 4976 grams is,

= 0.9544 * 2032

= 1939.3408

= 1939

Answer = 1939 babies .