Question

A) Assume that a sample is used to estimate a population proportion p. Find the 98% confidence interval for a sample of size 134 with 44 successes. Enter your answer as a tri-linear inequality using decimals (not percents) accurate to three decimal places.

_____ < p < _______

Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places.

B)Assume that a sample is used to estimate a population proportion p. Find the 99.5% confidence interval for a sample of size 219 with 81 successes. Enter your answer as an open-interval (i.e., parentheses) using decimals (not percents) accurate to three decimal places.

99.5% C.I. =
Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places.

C)If n=28, ¯xx¯(x-bar)=39, and s=9, find the margin of error at a 90% confidence level

Give your answer to two decimal places.

Answer 1

Refer Standard normal table/Z-table or use excel function "=NORM.S.INV((1-0.01))" to find the Z-value.

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Refer Standard normal table/Z-table or use excel function "=NORM.S.INV((1-0.0025))" to find the Z-value.

Note: Include open brackets in the answer.

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Refer t-table or use excel function "=T.INV.2T(0.10,27)" to find the value of t.