A simple random sample of 90 items from a population with = 7 resulted in a sample mean of 38.

If required, round your answers to two decimal places.

a.Provide a 90% confidence interval for the population mean.

.................... to 39.21

b.Provide a 95% confidence interval for the population mean.

36.55 to .................

c.Provide a 99% confidence interval for the population mean.

............... to 39.90

Q2-

For each of the values ofz_/2, determine the level of confidence (to 2 decimals).

z_/2= 1.91

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z_/2= 2.45

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z_/2= 2.56

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