Question

Scores on an IQ test are normally distributed. A sample of 5 IQ scores had standard deviation s=8. (a) Construct a 90% confidence interval for the population standard deviation . Round the answers to at least two decimal places. (b) The developer of the test claims that the population standard deviation is 15. Does this confidence interval contradict this claim? Explain.

Answer #1

a) At 90% confidence level, the critical values are

The 90% confidence interval for population standard deviation() is

b) No, the confidence interval does not contradict the claim. Because the population standard deviation value 15 lies in the confidence interval.

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on this sample. Then complete the table below.
Carry your intermediate computations to at least three decimal
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