# A random sample of 19 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:5, 6, 12, 10, 6, 8, 8, 11, 5, 9, 10, 12, 6, 12, 7, 9, 10, 8, 7Under the assumption that co-payment amounts are normally distributed, find a 95% confidence interval forthe mean co-payment amount in dollars. Then complete the table below.Carry your intermediate computations to at least three decimal places. Round your answers to one decimalplace. (If necessary, consult a list of formulas.)What is the lower limit of the confidenceinterval?What is the upper limit of the confidenceAainterval?

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Step 1

Step 2

The column above represents the sample data.

Sample size (n) = 19

The sample mean and sample standard deviation can be computed from the sample data as:

Step 3

Since, sample size is less than 30 and population standard deviation is not known therefore, t-would be applicable.

T-critical value at 0.05 significance level  with 18 degrees of freedom is –

t-critical value is taken from the t-able.

Thus, the 95% confidence interval can be computed as:

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