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Chapter 4: Q AP1.11. (page 278)


You are planning an experiment to determine the effect of the brand of gasoline and the weight of a car on gas mileage measured in miles per gallon. You will use a single test car, adding weights so that its total weight is

3000,3500, or 4000 pounds. The car will drive on a test track at each weight using each of Amoco, Marathon, and Speedway gasoline. Which is the best way to organize the study?

(a) Start with 3000 pounds and Amoco and run the car on the test track. Then do 3500 and 4000 pounds. Change to Marathon and go through the three weights in order. Then change to Speedway and do the three weights in order

once more.

(b) Start with 3000 pounds and Amoco and run the car on the test track. Then change to Marathon and then to Speedway without changing the weight. Then add weights to get 3500 pounds and go through the three types of gasoline in the same order. Then change to 4000 pounds and do the three types of gasoline in order again.

(c) Choose gasoline at random, and run the car with this gasoline at 3000,3500, and 4000 pounds in order. Choose one of the two remaining types of gasoline at random and again run the car at 3000, then 3500, then 4000 pounds. Do the same with the last gasoline.

(d) There are nine combinations of weight and gasoline. Run the car several times using each of these combinations. Make all these runs in random order.

(e) Randomly select an amount of weight and a brand of gasoline, and run the

car on the test track. Repeat this process a total of 30 times.

Short Answer

Expert verified

The correct option is (d).

Step by step solution

01

Given information

There are nine combinations of weight and gasoline.

02

Concept

A simple random sample (SRS) of size n is made up of n people chosen from the population with an equal chance of being the sample that is actually chosen.

03

Explanation

There are nine different weight and gasoline combinations. Because no randomization is used, if we provide one treatment first and then another, we will end up with a systematic error. Given a variety of options: Systematic errors, such as car warming up, are introduced by choices A,B, and C,D and Videos do not provide an evenly distributed set of tests. As a result, the ideal method to organize the research is to: There are nine different weight and gasoline combinations. Run the automobile through each of these combinations multiple times. Make each of these runs in a different order.

Option (d) is thus correct.

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Most popular questions from this chapter

Baseball tickets Suppose you want to know the average amount of money spent by the fans attending opening day for the Cleveland Indians baseball season. You get permission from the team’s management to conduct a survey at the stadium, but they will not allow you to bother the fans in the club seating or box seats (the most expensive seating). Using a computer,

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(a) Provide a reason why this survey might yield a biased result.

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subject is trained on the apparatus and then asked to make as many insertions as possible in 30 minutes of continuous effort.

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Suppose that a sample of households in a community is selected at random from the telephone directory. Explain how this sampling method results in under coverage that could lead to bias.

Archaeologists plan to examine a sample of 2-meter square plots near an ancient Greek city for artifacts visible in the ground. They choose separate random samples of plots from the floodplain, coast, foothills, and high hills. What kind of sample is this?

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Layoffs and “survivor guilt” Workers who survive a layoff of other employees at their location may suffer from “survivor guilt.” A study of survivor guilt and its effects used as subjects120students who were offered an opportunity to earn extra course credit by doing proofreading. Each subject worked in the same

cubicle as another student, who was an accomplice of the experimenters. At a break midway through the work, one of three things happened:

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