Question

The population of the birthweight of babies at a hospital, has a mean of 112 ounces and a standard deviation of 20.6 ounces. What is probability that a sample of the birthweights of the next 49 babies born at the hospital has a mean of more than 107 ounces.

	a) .0028
	b) .9616
	c) .0446
	d) .9545

Answer 1

Solution :

Given that ,

mean = = 112

standard deviation = = 20.6

n = 49

= 112 and

= / n = 20.6 / 49 = 2.9429

P( > 107) = 1 - P( < 107)

= 1 - P(( - ) / < (107 - 112) / 2.9429)

= 1 - P(z < -1.69)

= 1 - 0.0455

= 0.9545

Probability = 0.9545

option d) is correct