A matched pairs design t test is the best choice because it will compare the effectiveness of the fuel additive by looking at the means differences of two sample sets where the only variable that is changed from one test to the other test is the introduction of the fuel additive. It makes no sense to compare the performance of, for example, a Ford Mustang with the additive against a Toyota Prius hybrid without the additive. It becomes crucial to compare fuel efficiency with and without the fuel additive for each car.

Remember that a matched pairs design tends to involve "before and after" or "with and without" or "left and right" using the same experimental units.

Therefore comparing effectiveness of two coaches and their methods would not be an experiment for the matched pairs design.

The company wants a survey on what consumers want. That means they are interested in all possible consumers. The other groups are too specific. 

Since your teacher has asked that you determine the most popular cereal brand at your high school, the survey population should be limited to only your high school. Other students' preferences of cereal brands around the nation will have no impact on the survey results.

Additionally, surveying only students in your AP Statistics class or only students in a particular grade level would not be representative of all students in your high school. Therefore, the correct survey population is all students in your high school. 

Since Shawn would like to know the most popular television channel in his town, he must include all residents of the town in his target population. The sample must come from the directory and each person in the directory should have an equal chance of being selected. The incorrect options are too narrowly focused and are not representative of the town.

A continuous variable can take on an infinite continuum of possible real number values. Weight and the amount of time to read a book are continuous because it is impossible to write down all the distinct potential values. 

A binomial model counts the number of successes out of a specific number of attempts at a task when each attempt has a constant probability of success. The correct choice is the one that specifies the number of attempts. 

Taking a random sample is the only data-collecting method that ensures that every set of individuals has an equal chance of being selected for the sample and does not introduce any significant bias. Taking either a voluntary response sample or a convenience sample does not ensure these important aspects, as there is some unwanted selectivity involved in the data being collected. Taking a census is inferior to taking a sample of any sort, as it is both costly and time-consuming.

The best answer is the choice that reduces the amount of bias in the selection of survey participants. Surveying local residents at a grocery store, neighborhood park, or shopping mall would introduce selection bias into the survey since every member of the target population does not have an equal chance of being selected. Using the random number generator, every single person in the neighborhood has an equal chance of being selected to take the survey.

Because the survey is being conducted on drivers at a gas station, people/households who do not own a motor vehicle will not be included in the survey.