AP Stats-Semester 2 Review Name that Test! AP Stats-Semester 2 Review

In 1960, census results indicated that the age at which American men first married had a mean of 23.3 years. It is widely suspected that young people today are waiting longer to get married. We want to find out whether the mean age of men’s first marriage has increased during the past 40 years. The men in our sample of 40 married at an average of 24.2 years with a standard deviation of 5.3 years. 1

The Parents and Teens 2006 survey of 935 12 to 17-year-olds found that among teens aged 15-17 girls were significantly more likely to have used social networking sites and online profiles. 70% of the girls surveyed had used an online social network compared to 54% of the boys. Is it reasonable to believe that girls use social networking sites more than boys? 2

Researchers investigated how the size of a bowl affects how much ice cream people tend to scoop while serving themselves. At an ice cream social people were randomly given either a 17 oz or a 34 oz bowl. They were then invited to scoop as much ice cream as they liked. Did the bowl size change the selected portion size? Here are the summaries: Small Bowl Large Bowl n 26 22 5.07 6.58 3

Many people have trouble setting up all of the features on their cell phones, so a company has developed what it hopes will be easier instructions. The goal is to have at least 96% of customers succeed. The company tested the new system on 200 people of whom 188 were successful. Is this strong evidence that the new system fails to meet the company’s goal? 4

In a study of the television viewing habits of children, a developmental psychologist selects a random sample of 300 first graders; 100 boys and 200 girls. Each child is asked which of the following TV programs they like best: The Lone Ranger, Sesame Street, or The Simpsons. Do the boys’ preferences for these TV programs differ significantly from the girls’ preferences? 5

The USA Junior Chess Olympics Research described a study in which 6th grade students who had not previously played chess participated in a program where they took chess lessons and played daily for 9 months. Each student took a memory test before starting the program and again at the end of the 9 month period. The sample of 12 students had a mean difference of 144.58 and standard deviation of 109.74. The author of the article proposed using these data to test the theory that students who participated in the program tend to achieve higher memory scores. Is there evidence to support his claim? 6

The local utility company surveys 101 randomly selected customers The local utility company surveys 101 randomly selected customers. For each survey participant, the company collects the following: annual electric bill (in dollars) and home size (in square feet). Is there significant evidence of an association between annual bill and home size? 7

Who plays online or electronic games Who plays online or electronic games? A survey in 2006 found that 69% of 223 boys aged 12-14 said they played computer or console games like Xbox or PlayStation. Of the 248 boys aged 15-17 only 62% played these games. Is this evidence of a real age-based difference? 8

The Associated Press reported a management consultant believes that on average workers spend 75 minutes a day using personal use of company technology. Suppose that the CEO of a large corporation wants to determine whether the average amount of time spent on personal use for her employees is greater than the reported value of 75 minutes. The CEO did a random sample of 10 employees. The resulting data are: 66, 70, 75, 88, 69, 89, 71, 71, 63, 86. Do these data provide evidence that support the CEO’s claim? 9

In a certain town, there are about one million eligible voters In a certain town, there are about one million eligible voters. A simple random sample of 10000 eligible voters was chosen to study the relationship between gender and participation in the last election. Is there evidence that being a man or woman is independent of having voted in the last election? 10

1-Sample T – Test 2 Proportion Z Test 2 Sample T Test 1 Sample Z Test Chi2 Test for Homogeneity Matched Pairs Test Linear Regression Test 1 Sample T Test Chi2 Test of Independence