Calculate the margin of error and construct the confidence interval for the population mean using the Student's t-distribution (you may assume the population data is normally distributed).

T-Distribution Table

a. x=85.3,n=67,s=19.4,x=85.3,=67,=19.4, 80% confidence

E==

Round to two decimal places if necessary

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Round to two decimal places if necessary

b. x=39.7,n=44,s=10,x=39.7,=44,=10, 80% confidence

E==

Round to two decimal places if necessary

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Round to two decimal places if necessary