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1. Researchers were gathering data on alligators in an attempt to estimate an alligator's weight from its length. They captured 29 alligators and measured their length and weight. They created three regression models. Each model, along with its residual plot, is shown below. yrepresents the weight in pounds and xrepresents the length in inches.
Which statement is true?
2. A polling company has been asked to do a poll to see if the proportion of people that would vote for their candidate has improvedsince the previous poll, as their analyst suspects. Using pp= the proportion of all voters that would have supported their candidate in the previous poll, and pc= the proportion of all voters that would support their candidate in the current poll, which is an appropriate pair of hypotheses for a significance test?
3. A public health researcher suspected that there would be a relationship between the proportion of people in a state that engage in binge alcohol use and the proportion of people in the state that smoke cigarettes. A regression analysis was performed and some of the output is shown below.
What is the correlation coefficient for percent cigarette smokers and percent binge drinkers?
4. Marine biologists want to determine whether a small increase in the acidity of sea water would adversely affect marine life. They randomly assigned several Entacmaea quadricolor, one species of sea anemone, to one of eight aquariums that had been prepared with environments as similar as possible to the natural habitat. Then they randomly selected four tanks, and gradually increased the acidity of the water. They monitored the health of the anemones for the duration of the study. Which of these statements is NOT true about this study?
5. In a large high school, the student council wants to select a sample to survey the student body. They will first select 25 freshmen, then select 25 sophomores, then 25 juniors, and then finally 25 seniors. This is an example of a
Listed above are the summary statistics for the daily high temperatures (in degrees F) for the month of September in a Midwestern U.S. city. One particular day has a z-score of 0.70. What was the likely temperature that day?
7. In American football, the running back carries the football forward in a quest to score points. Many people create fantasy football teams by selecting players as their "team." These fans analyze data to judge which players are outstanding. The following regression output analyzes the linear relationship between the number of times a running back is given the football (carries) and the total number of yards that player gains in a season for a random sample of 18 running backs.
The appropriate calculation for a 99% confidence interval for the slope of the least squares regression line for the total yards gained versus number of carries in a season for all running backs is
Above is a cumulative relative frequency plot for the scores of a large university class on a 90-point statistics exam. Which of the following observations is correct?
9. Self-efficacy (the belief that one has control over one's situation) as it related to job satisfaction was studied. When a group of teachers rated their ability to control their situation and their satisfaction with their job, the two variables had a correlation of 0.30. Which statement follows from this correlation?
10. A university sent out a survey to a random sample of 120 recent graduates to see how those graduates feel about the education they received. Thirty-two of the graduates did not respond to the survey. Which of these would be the best way to proceed?