Confidence Intervals

Front

True or False: The more confident you want to be, the smaller your confidence interval will be.

Back

False

Front

Which of the following changes to a study would result in a smaller confidence interval?
Options:
increasing the confidence level, increasing the sample size;
increasing the confidence level, decreasing the sample size;
decreasing the confidence level, decreasing the sample size;
decreasing the confidence level, increasing the sample size.

Back

decreasing the confidence level, increasing the sample size.

Front

Which z-value is used for a 95% confidence interval?

Back

1.96

Front

The amount added and subtracted to the point estimate.

Back

Margin of Error

Front

What is the margin of error for the interval (6.8, 12.9)?

Back

3.05

Front

Identify the confidence interval used in the figure below if each shaded area is equal to 0.05.

Back

90%

Front

A research company wants to estimate the proportion of people who like oatmeal with a confidence level of 95%. They get 325 people to sign up for the survey, but only 250 show up. What happens to the confidence interval?

Back

It gets larger

Front

A sample of 20 cupcakes found the interval for average calories to be (150, 350). Which is the correct interpretation of the 95% confidence interval?

Back

We are 95% confident that the interval (150, 350) captures the true average caloric content.

Front

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?

Back

87% - 91%

Front

Does the interval (3, 14) support the claim that the mean of a data set is 2.9?

Back

No