Confidence Intervals

What is the effect of increasing sample size?

• increases margin of error and makes the interval wider

• decreases margin of error and makes the interval narrower

• increases margin of error and makes the interval narrower

• decreases margin of error and makes the interval wider

Tags

CCSS.HSS.IC.B.4

The capture rate (or hit percentage) of a sample of 100 intervals should most closely match the:

• Confidence level

• Margin of error

• Point estimate

• Confidence interval

Tags

CCSS.HSS.IC.B.4

Confidence intervals are used to estimate:

• the value of a sample statistic

• the margin of error

• the confidence level

• the value of a population parameter

Tags

CCSS.HSS.IC.B.4

Suppose an interval is (.62, .70). Margin of error =

• .04

• .08

• .66

• .74

Tags

CCSS.HSS.IC.B.4

You conduct a random survey in order to estimate the proportion of people of who are complying with social distancing guidelines. You expect some people will lie to make themselves look like better citizens. The primary effect of this response bias would be:

• to increase margin of error

• to decrease margin of error

• to make our point estimate higher than it actually is

• to make our point estimate lower than it actually is

Tags

CCSS.HSS.IC.B.3

When constructing intervals for sample proportions, our sample size must be:

• at least 10% of the population size

• large enough to produce 5 "successes" and 5 "failures"

• at least 30

• 1,000 people

Tags

CCSS.HSS.IC.B.4

When constructing a confidence interval for a proportion, we want to make sure our sample data and sample statistics are unbiased. The best way to ensure this is to:

• randomly select the sample

• ask a very large number of people

• not ask very personal questions

• ask the first 100 people you see.

Tags

CCSS.HSS.IC.B.4

You took a SRS of 1,012 people, and 678 said they are getting more sleep during the shelter in place than they were before. Which of these is the correct set up to find a 95% confidence interval?

•  $678\pm1.96\sqrt{\frac{.67\left(1-.67\right)}{1012}}$  

•  $.67\pm1.645\sqrt{\frac{.67\left(1-.67\right)}{1012}}$  

•  $.67\pm1.96\sqrt{\frac{.67\left(1-.67\right)}{678}}$  

•  $.67\pm1.96\sqrt{\frac{.67\left(1-.67\right)}{1012}}$  

Tags

CCSS.HSS.IC.B.4

You took a SRS of 1,012 people, and 263 said they are eating healthier during the shelter in place than they were before. Which of these is the margin of error for a 90% confidence interval?

• .0002

• .0138

• .0227

• .0270

Tags

CCSS.HSS.IC.B.4

A 95% confidence interval for the proportion of people who feel closer to their immediate family as a result of the shelter in place is (.44, .54). Does the interval provide convincing evidence that more than half of people now feel closer to their family?

• Yes, because .50 is contained in the interval and is a plausible value.

• No, because the middle of the interval is actually .49, which is less than half.

• No, because the interval has a margin of error, and so we think the interval is not correct.

• No because the interval is not entirely above .50. Some of the plausible values are less than 50%.

Tags

CCSS.HSS.IC.B.4