Ex 10.2.2

1. A sample of 16 students from a large university is taken. The average age in the sample

was 22 years with a standard deviation of 6 years. Suppose a 95% confidence interval

for the average age of the population is [x,y].

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(a) What is x? (to 1 digit)

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(b) What is y? (to 1 digit)

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2. You are given the following information obtained from a random sample of 4 observations.

25
47
32
56

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(a) What is the point estimate of Łg?

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(b) Suppose the 95% confidence interval for Łg is [x,y]. What is x?

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(c) Suppose the 90% confidence interval for Łg is [x,y]. What is y?

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3. A statistician selected a sample of 16 accounts receivable and determined the mean of

the sample to be $5000 with a standard deviation of $400. He reported that the sample

information indicated the mean of the population ranges from $4739.8 to $5260.2. What

is the confidence coefficient that was used.

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