Chapter 7: Sampling and Sampling Distributions

For this week read Chapter 7: Answer the following question:

Question 1

The data below represent the number of days absent per year in a population of three employees of a small company:

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a.Assuming that you sample without replacement, select all possible samples of n = 2 and construct the sampling distribution of the mean. Compare the mean of all the samples means and also compute the population mean. Are they equal? What is the property called?

b.Repeat (a) for all the sampling distribution of the mean in (a) for n= 3. Which sampling distribution has less variability? Why?

c.Assuming that you sample with replacement, repeat (a) through (c) and compare the results. Which sampling distribution have the least variability - those in (a) or (b) ? Why?

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Question 2

John surfs the website on a regular basis. Suppose the time he spent surfing the website per day is normally distributed, = 8 minutes and = 2 minutes. If you select a random sample of 4 sessions,

a.What is the probability that the sample mean is less than 8 minutes?

b.What is the probability that sample mean is between 8 and 10 minutes?

c.If you select a random sample of 16 sessions, what is the probability that a as sample mean is between 8 and 9 minutes?

d.Explain the differences in the results of (b) and (c).

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