WorksheetsHw 8 Ch. 8.1 - 8.3
Total questions: 17
Worksheet time: 1hrs 2mins
A college chemistry instructor thinks the use of embedded tutors (tutors who work with students during regular class meeting times) will improve the success rate in introductory chemistry courses. The passing rate for introductory chemistry is 62%. The instructor will use embedded tutors in all sections of introductory chemistry and record the percentage of students passing the course.
State the null and alternative hypotheses in words and in symbols. Use the symbol p to represent the passing rate for all introductory chemistry courses that use embedded tutors.
H0: p = 0.62
HA: p ≠ 0.62
The null hypothesis states that the pass rate is exactly 62% while the alternate hypothesis states that the pass rate is not 62%.
H0: p = 0.62
HA: p < 0.62
The null hypothesis states that the pass rate is exactly 62% while the alternate hypothesis states that the pass rate is less than 62%.
H0: p = 0.62
HA: p > 0.62
The null hypothesis states that the pass rate is exactly 62% while the alternate hypothesis states that the pass rate is greater than 62%.
H0: p ≠ 0.62
HA: p = 0.62
The null hypothesis states that the pass rate is not 62% while the alternate hypothesis states that the pass rate is exactly 62%.
According to a 2015 University of Michigan poll, 71.5% of high school seniors in the United States had a driver's license. A sociologist thinks this rate has declined. The sociologist surveys 500 randomly selected high school seniors and finds that 350 have a driver's license.
Pick the correct null hypothesis.
H0: p = 0.715
H0: p = 0.70
H0: p̂ = 0.715
H0: p̂ = 0.70
According to a 2015 University of Michigan poll, 71.5% of high school seniors in the United States had a driver's license. A sociologist thinks this rate has declined. The sociologist surveys 500 randomly selected high school seniors and finds that 350 have a driver's license.
Pick the correct alternate hypothesis.
HA: p > 0.715
HA: p < 0.715
HA: p̂ < 0.715
HA: p̂ ≠ 0.715
According to a 2015 University of Michigan poll, 71.5% of high school seniors in the United States had a driver's license. A sociologist thinks this rate has declined. The sociologist surveys 500 randomly selected high school seniors and finds that 350 have a driver's license.
In this context, the symbol p represents...
The proportion of high school seniors in the entire United States that have a driver's license.
The proportion of high school seniors in the sociologist's random sample that have a driver's license.
The National Association for Law Placement estimated that 86.7% of law school graduates in 2015 found employment. An economist thinks the current empl0yment rate for law school graduates is different from the 2015 rate.
Pick the correct pair of hypotheses the economist could use to test this claim.
H0: p ≠ 0.867
HA: p = 0.867
H0: p = 0.867
HA: p > 0.867
H0: p < 0.867
HA: p = 0.867
H0: p = 0.867
HA: p ≠ 0.867
St. Louis County is 24% African American. Suppose you are looking at jury pools, each with 200 members, in St. Louis County. The null hypothesis is that the probability of an African American being selected into the jury pool is 24%.
How many African Americans would you expect on a jury pool of 200 people if the null hypothesis is true?
(a)
St. Louis County is 24% African American. Suppose you are looking at jury pools, each with 200 members, in St. Louis County. The null hypothesis is that the probability of an African American being selected into the jury pool is 24%.
Suppose pool A contains 40 African American people out of 200, and pool B contains 26 African American people out of 200. Which will have a smaller p-value?
Pool A because the number of African Americans in the jury pool is closer to the expected number given by the null hypothesis.
Pool A because the number of African Americans in the jury pool is farther from the expected number given in the null hypothesis.
Pool B because the number of African Americans in the jury pool is closer to the expected number given the null hypothesis.
Pool B because the number of African Americans in the jury pool is farther from the expected number given by the null hypothesis.
According to a Gallup poll, 11.55% of American adults have diabetes. Suppose a researcher wonders if the diabetes rate in her area is higher than the national rate. She surveys 150 adults in her area and finds that 21 of them have diabetes.
If the region had the same rate of diabetes as the rest of the country, how many would we expect to have diabetes?
(Round your answer to the nearest whole number.)
(a)
According to a Gallup poll, 11.55% of American adults have diabetes. Suppose a researcher wonders if the diabetes rate in her area is higher than the national rate. She surveys 150 adults in her area and finds that 21 of them have diabetes.
Suppose you are testing the hypothesis that the diabetes rate in this area differs from the national rate, using a 0.05 significance level. Choose the correct figure to represent the p-value of the hypothesis test.
According to a Gallup poll, 11.55% of American adults have diabetes. Suppose a researcher wonders if the diabetes rate in her area is higher than the national rate. She surveys 150 adults in her area and finds that 21 of them have diabetes.
Suppose you are testing the hypothesis that the diabetes rate in this area differs from the national rate, using a 0.05 significance level. The p-value of this test is 0.3478. Choose the correct interpretation of the p-value.
The probability of randomly selecting a sample with a rate of diabetes as extreme or more extreme than that of the sample proportion is 0.3478.
The probability of randomly selecting a sample with a rate of diabetes higher than that of the sample proportion is 0.3478.
The probability of randomly selecting a sample with a rate of diabetes less than that of than the sample proportion is 0.3478.
The probability of randomly selecting a sample with a rate of diabetes equal to the sample proportion is 0.3478.
Suppose we are testing people to see whether the rate of use of seat belts has changed from a precious value of 88%. Suppose that in our random sample of 500 people we see that 450 have the seat belt fastened. Which of the following figures has the correct p-value for testing the hypothesis that the proportion who use seat belts has changed?
A 2018 Gallup poll of 2228 randomly selected U.S. adults found that 39% planned to watch at least a "fair amount" of the 2018 Winter Olympics. In 2014, 46% of U.S. adults reported planning to watch at least a "fair amount."
Does this sample give evidence that the proportion of U.S. adults who planned to watch the 2018 Winter Olympics was less than the proportion who planned to do so in 2014? Use a 0.05 significance level.
Reject the null hypothesis; we can conclude that the proportion of adults who planned to watch the Winter Olympics in 2018 is significantly less than that of 2014.
Reject the null hypothesis; we can conclude that the proportion of adults who planned to watch the Winter Olympics in 2018 is not significantly less than that of 2014.
Fail to reject the null hypothesis; we can conclude that the proportion of adults who planned to watch the Winter Olympics in 2018 is significantly less than that of 2014.
Fail to reject the null hypothesis; we can conclude that the proportion of adults who planned to watch the Winter Olympics in 2018 is not significantly less than that of 2014.
A 2018 Gallup poll of 2228 randomly selected U.S. adults found that 39% planned to watch at least a "fair amount" of the 2018 Winter Olympics. In 2014, 46% of U.S. adults reported planning to watch at least a "fair amount."
After conducting the hypothesis test, a further question one might ask is what proportion of all U.S. adults planned to watch at least a "fair amount" of the 2018 Winter Olympics. Use the sample data to construct a 90% confidence interval for the population proportion.
(Give your answer in the form " (#,#) " with no spaces, use percentages rounded to the nearest whole percent.)
(a)
A 2018 Gallup poll of 2228 randomly selected U.S. adults found that 39% planned to watch at least a "fair amount" of the 2018 Winter Olympics. In 2014, 46% of U.S. adults reported planning to watch at least a "fair amount."
Explain how the results of your confidence interval support the results of your hypothesis test.
According to one source, 50% of plane crashes are due at least in part to pilot error. Suppose that in a random sample of 100 separate airplane accidents, 62 of them were due to pilot error (at least in part).
Test the hypothesis that the proportion of airplane accidents due to pilot error is not 0.50. Use a significance level of 0.05.
Reject the null hypothesis; there is sufficient evidence to conclude that the proportion of airplane accidents is significantly different from 0.50.
Reject the null hypothesis; there is sufficient evidence to conclude that the proportion of airplane accidents is not significantly different from 0.50.
Fail to reject the null hypothesis; there is sufficient evidence to conclude that the proportion of airplane accidents is significantly different from 0.50.
Fail to reject the null hypothesis; there is sufficient evidence to conclude that the proportion of airplane accidents is not significantly different from 0.50.
If we do not reject the null hypothesis, is it valid to say that we accept the null hypothesis? Why or why not?
A weight-loss diet claims that it causes weight loss by eliminating carbohydrates (breads and starches) from the diet. To test this claim, researchers randomly assign overweight subjects to two groups. Both groups eat the same amount of calories, but one group eats almost no carbs, and the other group includes carbs in their meals. After 2 months, the researchers test the claim that the no-carb diet is better than the usual diet. They record the proportion of each group that lost more than 5% of their initial weight. They then announce that they failed to reject the null hypothesis. Which of the following are valid interpretations of the researchers' findings?
There were no significant differences in effectiveness between the no-carb diet and the carb diet.
The no-carb diet and the carb diet were equally effective.
The researchers did not see enough evidence to conclude that the no-carb diet was more effective.
The no-carb diet was less effective than the carb diet.
