Margin Error Confidence Interval

A 99% confidence interval for a population mean is (100, 200). What is the margin of error?

• 50

• 100

• 150

• 200

To decrease the margin of error in a confidence interval, you should:

• Increase the confidence level

• Decrease the sample size

• Increase the sample size

• Decrease the confidence level

If the margin of error in a confidence interval is 8 and the sample mean is 200, what is the lower bound of the confidence interval?

• 192

• 196

• 200

• 208

A survey estimates that 45% of voters favor candidate A with a margin of error of 4%. What is the confidence interval for the proportion of voters who favor candidate A?

• (0.41, 0.49)

• (0.39, 0.51)

• (0.43, 0.47)

• (0.45, 0.49)

The amount added and subtracted to the statistic.

• Margin of error

• Statistic

• Population

• Point estimator

The National Honor Society at Central High School plans to sample a random group of 100 seniors from all high schools in the state to determine the average number of hours per week spent on homework. A 95 percent confidence interval for the mean number of hours spent on homework will then be constructed using the sample data. Before selecting the sample, the National Honor Society decides that it wants to decrease the margin of error. Which of the following is the best way to decrease the margin of error?

• Increase the confidence level to 99%

• Use the population standard deviation

• Use the sample standard deviation

• Decrease the sample size

• Increase the sample size

What is the margin of error of this sample?

• .21

• .344

• .14

• .342

The amount added and subtracted to the sample statistic.

• Margin of Error

• Point Estimator

• Statistic

• Population

A recent survey found that out of 400 random American adults, 89% pay their bills on time. The margin of error in this survey was 2%. What is the interval of values in which the truth is likely found?

• 89% - 91%

• 87% - 89%

• 87% - 91%

• 388 - 402

Margin of Error is equal to:

• Standard Deviation

• 2 * Standard Deviation

• Critical Value

• Point Estimate