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=86.8,n=66,s=13.7, 80% confidence

E=

Round to two decimal places if necessary

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Round to two decimal places if necessary

b. x=37.8,n=43,s=13.7,98% confidence

E=

Round to two decimal places if necessary

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Round to two decimal places if necessary