A random sample of 20 health maintenance organizations (HMOs) was selected. For each HMO, the co-payment (in dollars) for a doctor's office visit was recorded. The results are as follows.
12, 7, 11, 8, 12, 8, 5, 8, 9,7, 6, 6, 7, 10, 5, 9, 6, 11, 9, 12
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a
Under the assumption that co-payment amounts are normally distributed, find a 99% confidence interval for the mean co-payment amount in dollars. Then find
the lower limit and upper limit of the 99% confidence interval.
Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.)
Lower limit:
Upper limit: 0
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5
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