Question

The diameter of small Nerf bars manufactured overseas is expected to be approximately normally distributed with a mean of 5.2 inches and a standard deviation of .08 inches. Suppose a random sample of 20 balls are selected. What percentage of sample means will be less than 5.14 inches?

A. 0.043%

B. 22.66%

C. 4.3%

D. 0.00043%

Answer 1

Solution :

Given that ,

mean = = 5.2

standard deviation = = 0.08

n = 20

= 5.2 and

= / n = 0.08 / 20 = 0.01789

P( < 5.14) = P(( - ) / < (5.14 - 5.2) / 0.01789)

= P(z < -3.333)

= 0.00043

Answer = 0.043%

A)