1) Which of the following options will cause a decrease in the margin of error for a confidence interval?

• Increase the confidence
• Decrease the sample size
• Increase the sample size
• Decrease the sample size and increase the confidence

2) Which of the following options will cause a decrease in the margin of error for a confidence interval?

• Increase the confidence
• Decrease the confidence level
• Decrease the sample size
• Decrease the sample size and increase the confidence

3) For a confidence level of 98%, find the critical Z value

4) You measure 31 textbooks' weights, and find they have a mean weight of 47 ounces. Assume thepopulation standard deviationis 9.3 ounces. Based on this, construct a 90% confidence interval for the true population mean textbook weight.

Give your answers correct to at least two decimal places.

Lower Limit =

Upper Limit =

5) You want to obtain a sample to estimate a population mean age of the incoming fall term transfer students. Based on previous evidence, you believe the population standard deviation is approximately=5.5=5.5. You would like to be 90% confident that your estimate is within 1.8 of the true population mean. How large of a sample size is required?

n=

Do not round between steps. Use technology to find z-score. Give your answer in whole people. Make sure you use the correct rounding rule for samples size.

6) Which of the following would result in thewidestconfidence interval?

a sampe size of 300 with95%95%confidence

a sampe size of 300 with80%80%confidence

a sampe size of 300 with98%98%confidence

a sampe size of 300 with99%99%confidence

a sampe size of 300 with90%90%confidence

7) What is the correct critical value of t for a 90% confidence interval with a sample size of 23?

• 2.074
• 1.714
• 1.717
• 2.069

8) For a confidence level of 99% with a sample size of 28, find the criticaltvalue.

9) Ifn=n=10,x=x=49, ands=s=3, find the margin of errorEEat a 80% confidence level

Give your answer to two decimal places.

10) If n=32,xx(x-bar)=40, and s=19, construct a confidence interval at a 90% confidence level. Assume the data came from a normally distributed population.

Give your answers to one decimal place.

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