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1) In a random sample of 49 audited estate tax returns, it was determined that t

ID: 3220372 • Letter: 1

Question

1) In a random sample of 49 audited estate tax returns, it was determined that the mean amount of additional tax owed was $3453 with a standard deviation of $2537. Construct and interpret a 90% confidence interval for the mean additional amount of tax owed for estate tax returns.

The lower bound is: (round to the nearest dollar as needed)

The upper bound is: (round to the nearest dollar as needed).

2) In a random sample of 64 audited estate tax returns, it was determined that the mean amount of additional tax owed was $3413 with a standard deviation of $2516. Construct and interpret a 90% confidence interval for the mean additional amount of tax owed for estate tax returns.

The lower bound is: (round to the nearest dollar as needed)

The upper bound is: (round to the nearest dollar as needed)

Explanation / Answer

(1)

n = 49     

x-bar = 3453     

s = 2537     

% = 90     

Standard Error, SE = s/n =    2537/49 = 362.4285714

Degrees of freedom = n - 1 =   49 -1 = 48   

t- score = 1.677224197     

Width of the confidence interval = t * SE =     1.67722419660282 * 362.428571428571 = 607.8739695

Lower Limit of the confidence interval = x-bar - width =      3453 - 607.873969540194 = 2845.12603

Upper Limit of the confidence interval = x-bar + width =      3453 + 607.873969540194 = 4060.87397

The 90% confidence interval is [$2845, $4061]