The mean weight of 20 randomly selected newborn babies at a local hospital is 7.03 lbs and the standard deviation is 0.6 lbs. Assume the weight of newborn babies has approximately normal distribution.

(a) Find the margin of error for the 80% confidence interval for the mean weight of all newborn babies at this hospital. (Round your answer to two decimal places.)

(b) Use information from part (a) to fill in the banks in the following sentence:% of all samples of sizehave sample means withinlbs of the population mean.

(c) Find a 80% confidence interval for the mean weight of all newborn babies at this hospital. (Round your answer to two decimal places.)

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(d) Does the confidence interval, at 80% level, provide sufficient evidence that the mean weight of a newborn at this hospital is above 6.8 lbs? Write the appropriate inequality to justify your answer.

(e) If you increase the confidence level (1), will the confidence interval estimate be wider or narrower? Explain.