Question

A study studied the birth weight of 2,817 babies born in the United States. The mean weight was 3334 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

Answer 1

Solution :

Given that ,

mean = = 3334

standard deviation = = 871

P(1492 < x < 4976) = P[(1492 - 3334)/ 871) < (x - ) /  < (4976 - 3334) / 871) ]

= P(-2.11 < z < 1.89)

= P(z < 1.89) - P(z < -2.11)

Using z table,

= 0.9706 - 0.0174

= 0.9532

= 2817 * 0.9532 = 2685.16

= 2685 newborns.