U6D6 Quiz Grade Review Questions Feb12/13

Last updated 9 months ago

25 questions

U6D6 Quiz Grade Review Questions Feb12/13

Last updated 9 months ago

25 questions

Interpreting a Confidence Interval

Unused Subscriptions
A random sample of 100 adults were asked if they pay for monthly subscriptions they do not use – such as gym memberships or music and video streaming apps. Many people say they keep these subscriptions because they hope to use them more or that it is hard to cancel the subscription. 
A 95% confidence interval for the true proportion of adults who pay for subscriptions they do not use is 0.352 to 0.548.

Interpret the confidence interval.

Calculate the point estimate and the margin of error.

point estimate = _______ 
margin of error = _______ 

Based upon this survey, a reporter claims that a majority of adults continue to pay for monthly subscriptions they do not use. Use the confidence interval to evaluate this claim.

Interpreting a Confidence Level

Can You Pull Up?
The physical education teacher at a large high school wants to estimate the proportion of students at this school that can do a pullup. He selects a random sample of 30 students from those who are available after school for sports practices. He records whether or not each student in the sample can do a pullup. He determines that he is 90% confident that the interval from 0.418 to 0.715 captures the true proportion of all students at this school that can do a pullup.

Interpret the confidence interval.

Interpret the confidence level.

Introduction to Significance Tests

Thanks Mom!
Factinate.com claims that 84% of teenagers think highly of their mother. To investigate this claim, a school psychologist selects a random sample of 150 teenagers and finds that 132 think highly of their mother. Do these data provide convincing evidence that the true proportion of teens who think highly of their mother is greater than 0.84?

State appropriate hypotheses for performing a significance test. Be sure to define the parameter of interest.

Do the results provide some evidence for Ha? Explain.

The school psychologist performed the significance test and obtained a p-value of 0.091. Interpret the p-value.

Conditions and p-value

Yummy Cilantro?
For most people cilantro is a delicious spice that can be added to many recipes, but for some it has a terrible soapy flavor. Scientists believe that about 10% of the population tastes this soapy flavor. Ebise can taste the soapy flavor and believes that it affects more than 10% of teenagers. She takes a random sample of 200 teenagers and finds that 25 of them get the soapy flavor. Do these results provide convincing evidence that more than 10% of teenagers get a soapy flavor for cilantro? Use alpha = 0.05.

State appropriate hypotheses for performing a significance test. Be sure to define the parameter of interest.

Significance Tests for a Proportion

Phone Addicted Teens
CNN once claimed that half of teenagers are addicted to their phones. A random sample of 180 teenagers was selected and 72 reported they were addicted to their phones. Is there convincing statistical evidence that the proportion of all teenagers who are addicted to their phones differs from 0.50? Use alpha = 0.05.

U6D6 Quiz Grade Review Questions Feb12/13

U6D6 Quiz Grade Review Questions Feb12/13

Interpreting a Confidence Interval

Interpret the confidence interval.

Based upon this survey, a reporter claims that a majority of adults continue to pay for monthly subscriptions they do not use. Use the confidence interval to evaluate this claim.

Interpreting a Confidence Level

Interpret the confidence interval.

Interpret the confidence level.

Introduction to Significance Tests

State appropriate hypotheses for performing a significance test. Be sure to define the parameter of interest.

Do the results provide some evidence for Ha? Explain.

The school psychologist performed the significance test and obtained a p-value of 0.091. Interpret the p-value.

Conditions and p-value

State appropriate hypotheses for performing a significance test. Be sure to define the parameter of interest.

Significance Tests for a Proportion

State appropriate hypotheses for performing a significance test. Be sure to define the parameter of interest.

Interpreting a Confidence Interval

Interpret the confidence interval.

Based upon this survey, a reporter claims that a majority of adults continue to pay for monthly subscriptions they do not use. Use the confidence interval to evaluate this claim.

Interpreting a Confidence Level

Interpret the confidence interval.

Interpret the confidence level.

How would a 90% confidence interval from a sample of size 200 compare to the original 90% interval? Explain

Explain what would happen to the length of the interval if the confidence level were decreased to 80%.

Describe one potential source of bias in this study that is not accounted for by the margin of error.

Introduction to Significance Tests

State appropriate hypotheses for performing a significance test. Be sure to define the parameter of interest.

Do the results provide some evidence for Ha? Explain.

The school psychologist performed the significance test and obtained a p-value of 0.091. Interpret the p-value.

At the 0.05 level, do the results provide convincing evidence that true proportion of teens who think highly of their mother is greater than 0.84?

Conditions and p-value

State appropriate hypotheses for performing a significance test. Be sure to define the parameter of interest.

Explain why the sample result gives some evidence for the alternative hypothesis.

Check if the conditions for performing the significance test are met.

Interpret the p-value.

What conclusion should Ebise make?

Significance Tests for a Proportion

State appropriate hypotheses for performing a significance test. Be sure to define the parameter of interest.

Explain why the sample result gives some evidence for the alternative hypothesis.

Check if the conditions for performing the significance test are met.

Interpret the p-value.

What conclusion should we make?

A 95% confidence interval for the proportion of all teenagers who are addicted to their phones is (0.328, 0.472). Explain how the confidence interval is consistent with the significance test.

How would a 90% confidence interval from a sample of size 200 compare to the original 90% interval? Explain

Explain what would happen to the length of the interval if the confidence level were decreased to 80%.

Describe one potential source of bias in this study that is not accounted for by the margin of error.

At the 0.05 level, do the results provide convincing evidence that true proportion of teens who think highly of their mother is greater than 0.84?

Explain why the sample result gives some evidence for the alternative hypothesis.

Check if the conditions for performing the significance test are met.

Interpret the p-value.

What conclusion should Ebise make?

Explain why the sample result gives some evidence for the alternative hypothesis.

Check if the conditions for performing the significance test are met.

Interpret the p-value.

What conclusion should we make?

A 95% confidence interval for the proportion of all teenagers who are addicted to their phones is (0.328, 0.472). Explain how the confidence interval is consistent with the significance test.