Intro to Confidence Intervals

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?

• We are 95% confident that the true mean caloric content can be found with a sample of 150 to 350 cupcakes.

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

• We are 95% confident that a sample of 20 cupcakes will find 250 calories per cupcake.

• None of these are correct.

Which of the following changes to a study would result in a narrower confidence interval?

• increasing the confidence level, increasing the sample size

• decreasing the confidence level, decreasing the sample size

• increasing the confidence level, decreasing the sample size

• decreasing the confidence level, increasing the sample size.

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

• 9.85

• 3.05

• 3.50

• 6.8

If the 95% Confidence Interval for a population mean is (114.56, 125.54), then is it likely that the true population mean µ is greater than 130?

• Yes

• No

• Not Enough Information

• What?

A 95% confidence interval was conducted on American adults aged 45-64 and found that the between 15.7% and 19.4% had diabetes as of 2016.

a) What is the population proportion that has diabetes according to this confidence interval? ​ (a)  

b) What was the margin of error associated with this data? ​ (b)  

• 17.55%

• 1.85%

• 11.55

• 5.775

• 11.55%

• 5.775%

Percentiles of the bootstrap distribution are provided. Use the percentiles to report a 95% confidence interval for the parameter.

• 6.593 hours to 7.78 hours

• 6.322 hours to 8.082 hours

• 6.438 hours to 7.947 hours

• 6.174 hours to 8.304 hours

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

• 90%

• 95%

• 98%

• 99%

Match the following Intervals to their confidence level.

All intervals calculated using the same standard deviation and sample size.

• 11.5 < μ < 12.7

• 99%

• 9.7 < μ < 10.3

• 90%

• 7.7 < μ < 8.7

• 95%

• 15.2 < μ < 16.0

• 80%

• A
• B
• C
• D

What is the point estimator for the interval (-5 , 13)?

• 10

• 9.5

• 9

• -5