PROBLEM 1: A laptop manufacturer finds that the average time it takes an employe

Question

PROBLEM 1:

A laptop manufacturer finds that the average time it takes an employee to load a laptop with software is 40 minutes with a standard deviation 15 minutes. Suppose you take a random sample of 81 employees. The standard deviation of the sample mean is:

Standard Deviation

PROBLEM 2:

A company that manufactures bookcases finds that the average time it takes an employee to build a bookcase is 23 hours with a standard deviation of 8 hours. A random sample of 64 employees is taken. What is the likelihood that the sample mean will be 26 hours or more?

Probabilistic Likelihood

Standard Deviation

Explanation / Answer

Problem1

The standard deviation of mean=sigma/root(n)=15/sqrt(9)=5minutes

Problem2

Mean=23

sample size=64

standard dev=8

Hence standard dev of mean=8/sqrt(64)=1

Hence for 26hrs or more=(26-23)/1 =3 standard deviations to the right of mean

Hence Z(3)=0.99865

Hence the likelihood of 26hrs or more=1-0.99865=0.00135=0.135%

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