Ch 16 Confidence Intervals Practice

4

In January 2002, two students made worldwide headlines by spinning a Belgian euro coin 250 times and getting 140 heads- that's 56%. That makes the 90% confidence interval (51%, 61%). What does this mean? Choose the correct answer.

4

A Pew Research study regarding cell phones asked questions about cell phone experience. One growing concern is unsolicited advertising in the form of text messages. When questioned, 17% of the adults surveyed reported that they had received unsolicited advertising in the form of text messages. Pew estimates a 95 confidence interval to be:
This would be between 13% and 21%.
Which statement about the people who have cell phones is correct?

4

A study of 902 decisions made by the Nebraska Board of Parole produced the following range for a 95% confidence interval: (0.561, 0.625). Use what you know about how a confidence interval is calculated to find the expected proportion (p-hat) for the Sampling Distribution.
Remember:

Keep the decimal rounded to three places after the decimal point.

4

A study of 902 decisions made by the Nebraska Board of Parole produced the following range for a 95% confidence interval: (0.561, 0.625). Use what you know about how a confidence interval is calculated to find the standard error for the Sampling Distribution.
Remember:

Keep the decimal rounded to three places after the decimal point.

4

According to the Red Cross, about 42% of Americans have Type A blood. Suppose 80 people show up at a typical blood drive.
What is the expected proportion of people who are Type A?
This is a review from Thurs/Fri of last week.

4

According to the Red Cross, about 42% of Americans have Type A blood. Suppose 80 people show up at a typical blood drive. What is the standard deviation of the Type A proportion at blood drives when 80 people donate blood?
Round to three places after the decimal point.
Hint: this is a review from last week on Thurs/Friday.

4

According to the Red Cross, about 42% of Americans have Type A blood. Suppose 80 people show up at a typical blood drive. What is the margin of error for a 95% confidence interval?
Remember:
Round your answer to three places past the decimal.

4

According to the Red Cross, about 42% of Americans have Type A blood. Suppose 80 people show up at a typical blood drive. Create a 95% confidence interval for the proportion of donors who will have Type A blood at a blood drive with 80 donors.

Round to three places past the decimal.
Use the notation used in class (, _) put a space after the comma.

4

A consumer group, hoping to assess customer experiences with auto dealers, surveys 167 people who recently purchased new cars.
3% of them expressed disatisfaction with the salesperson.
Can we use a Normal Model to represent the Sampling Distribution of the proportion of people who are disatisfied with their new car purchase?
Check the assumptions and conditions.

4

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once. Can we use the Normal Model to represent the Sampling Distribution of the proportion of students that cheat in high school?

4

What percent of college students have cell phones? 2883 college students were asked as they entered a football stadium, and 2432 said they had phones with them. Can we use a Normal Model to represent the Sampling Distribution of the proportion of college students who have cell phones?

4

A school is considering requiring students to wear uniforms. The PTA surveys parent opinion by sending a questionnaire home with all the 1245 students: 380 surveys are returned, with 228 families in favor of the change. Can we use a Normal Model to represent the Sampling Distribution for the proportion of families that are in favor of school uniforms?

4

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once.
Find the sample proportion (phat):
Round to four places past the decimal.

4

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once. Estimate the variability in the sampling distribution by finding the Standard Error, SE(phat):
Use the formula from class.
Round to four places past the decimal

4

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once. Before you create a 95% confidence interval, use the Standard Error from #14 and find the Margin of Error for a 95% confidence interval.
For 95% Confidence Interval the ME is 2 times the SE.
Hint: how many SE above and below the mean is used?
Round to three places past the decimal.

4

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once. Since we already decided it is appropriate to use the Normal Model to describe the sampling distributions of students who cheat, create a 95% confidence interval.

Set up the interval using the notation we used in class.
Round to three places past the decimal.

4

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once. In # 15 you created a 95% confidence interval, what does this tell us?

4

A nationwide nutrition study by the Centers for Disease Control reported that out of 1815 randomly selected high school students, 517 said they were current smokers.
Calculate the sample proportion (phat).
Round to three places past the decimal.

4

A nationwide nutrition study by the Centers for Disease Control reported that out of 1815 randomly selected high school students, 517 said they were current smokers.
Calculate the Standard Error, SE(phat):
Round to three places past the decimal.

4

A nationwide nutrition study by the Centers for Disease Control reported that out of 1815 randomly selected high school students, 517 said they were current smokers.
Use the information from #18 & 19 to create a 95% confidence interval for the proportion of HS students who smoke.

Set up the interval using the notation we used in class.

In January 2002, two students made worldwide headlines by spinning a Belgian euro coin 250 times and getting 140 heads- that's 56%. That makes the 90% confidence interval (51%, 61%). What does this mean? Choose the correct answer.

According to the Red Cross, about 42% of Americans have Type A blood. Suppose 80 people show up at a typical blood drive. What is the expected proportion of people who are Type A?This is a review from Thurs/Fri of last week.

According to the Red Cross, about 42% of Americans have Type A blood. Suppose 80 people show up at a typical blood drive. What is the margin of error for a 95% confidence interval?Remember:Round your answer to three places past the decimal.

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once. Can we use the Normal Model to represent the Sampling Distribution of the proportion of students that cheat in high school?

What percent of college students have cell phones? 2883 college students were asked as they entered a football stadium, and 2432 said they had phones with them. Can we use a Normal Model to represent the Sampling Distribution of the proportion of college students who have cell phones?

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once.Find the sample proportion (phat): Round to four places past the decimal.

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once. In # 15 you created a 95% confidence interval, what does this tell us?

A nationwide nutrition study by the Centers for Disease Control reported that out of 1815 randomly selected high school students, 517 said they were current smokers.Calculate the sample proportion (phat).Round to three places past the decimal.

A nationwide nutrition study by the Centers for Disease Control reported that out of 1815 randomly selected high school students, 517 said they were current smokers.Calculate the Standard Error, SE(phat):Round to three places past the decimal.

According to the Red Cross, about 42% of Americans have Type A blood. Suppose 80 people show up at a typical blood drive.
What is the expected proportion of people who are Type A?
This is a review from Thurs/Fri of last week.

According to the Red Cross, about 42% of Americans have Type A blood. Suppose 80 people show up at a typical blood drive. What is the margin of error for a 95% confidence interval?
Remember:
Round your answer to three places past the decimal.

Rutgers University surveyed 4,500 randomly selected high school students nationwide: 3,329 of these students admitted they had cheated on a test at least once.
Find the sample proportion (phat):
Round to four places past the decimal.

A nationwide nutrition study by the Centers for Disease Control reported that out of 1815 randomly selected high school students, 517 said they were current smokers.
Calculate the sample proportion (phat).
Round to three places past the decimal.

A nationwide nutrition study by the Centers for Disease Control reported that out of 1815 randomly selected high school students, 517 said they were current smokers.
Calculate the Standard Error, SE(phat):
Round to three places past the decimal.