Question

An operation manager at an electronics company wants to test their amplifiers. The design engineer claims they have a mean output of 495 watts with a standard deviation of 12 watts.

What is the probability that the mean amplifier output would be greater than496.1 watts in a sample of 88 amplifiers if the claim is true? Round your answer to four decimal places.

Answer 1

Solution :

Given that,

mean = = 495

standard deviation = = 12

n = 88

= = 495

= / n = 12 / 88 = 1.28

P( > 496.1) = 1 - P( < 496.1)

= 1 - P[( - ) / < (496.1 - 495) /1.28 ]

= 1 - P(z < 0.86)

Using z table,    

= 1 - 0.8051

= 0.1949