AP StatisticsName: ______
Chapter 20-22 Review
The stats teacher is concerned that only 42% of the students are passing. An administrator suggests that she invest in a new teaching method that will include daily quizzes. The teacher tries the new method for one chapter to determine if the grades increase.
1.Write the teacher’s null and alternative hypotheses in context. Clearly define the variables used.
2.In this context describe a Type I error and the impact such an error would have on the grades/students/teacher.
3.In this context describe a Type II error and the impact such an error would have on the grades/students/teacher.
4.A. Based on the data collected during the trial the teacher found that a 95% confidence interval for the proportion of all students who might increase their grade was (51%, 59%). What conclusion should the teacher reach about the new teaching method? Explain.
B. Based on the data collected during the trial the teacher found that a 95% confidence interval for the proportion of all students who might increase their grade was (41%, 45%). What conclusion should the teacher reach about the new teaching method? Explain.
5.If the teacher were to conduct the trials over a longer period of time (ie. she will have a larger sample size), would the power of the test increase or decrease? Explain.
Nebraska has a great football tradition. We assume we attend more games then most other states. Iowa feels that they have a higher percentage of football attendees. A recent “True” poll reported that 58% of 2010 randomly sampled Nebraskans attended at least one game in the past year, compared to 61% of 1600 randomly sampled Iowans. Do these results confirm a higher attendance rate in Iowa?
1.Test an appropriate hypothesis and state your conclusions.
2.Find a 95% confidence interval for the difference in the proportion of Nebraskans and Iowans who attended at least one game in the last year. Interpret your interval.
In the December 2002 issue of Consumer Reports, Consumers Union reported on their
investigation of the presence of bacteria in packages of chicken sold in supermarkets.
• They purchased both name brand (Perdue) and store brand chicken in 25 U.S. cities.
Laboratory tests found campylobacter contamination in 33% of the 75 Perdue packages,
and in 45% of the 75 store brand packages. Does this study provide sufficient evidence at the level to suggest that shoppers would be safer buying the name brand product?
In 2000, the United Nations claimed that there was a higher rate of illiteracy in men than in women
from the country of Qatar. A humanitarian organization went to Qatar to conduct a random
sample. The results revealed that 45 out of 234 men and 42 out of 251 women were classified as
illiterate on the same measurement test. Does this study provide sufficient evidence at the level to suggest that the United Nations findingswere correct?