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Stop doing homework! (4.3)Researchers in Spain interviewed 772513-year-olds about their homework habits—how much time they spent per night on homework and whether they got help from their parents or not—and then had them take a test with 24math questions and 24science questions. They found that students who spent between 90and 100minutes on homework did only a little better on the test than those who spent 60to 70minutes on homework. Beyond 100minutes, students who spent more time did worse than those who spent less time. The researchers concluded that 60to 70minutes per night is the optimum time for students to spend on homework.32 Is it appropriate to conclude that students who reduce their homework time from 120minutes to 70minutes will likely improve their performance on tests such as those used in this study? Why or why not? independent random samples from two populations of interest or from two groups in a randomized experiment, use two-sample t procedures for μ1−μ23051526=0.200=20.0%μ1-μ2

Short Answer

Expert verified

The required answer is No

Step by step solution

01

Explanation

In the previous exercise, we concluded that there was a link between homework time and test performance, such as those used in the study, because homework times longer than 100minutes tend to correspond with poor test results.

However, association does not imply causation, which means that reducing homework time does not always result in better test results.

02

For example

It is possible that people with long homework times have learning difficulties, and that reducing their homework time will worsen their test results.

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Most popular questions from this chapter

Which inference method?

a. Drowning in bathtubs is a major cause of death in children less than5years old. A random sample of parents was asked many questions related to bathtub safety. Overall,85%of the sample said they used baby bathtubs for infants. Estimate the percent of all parents of young children who use baby bathtubs.

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c. You have data from interviews with a random sample of students who failed to graduate from a particular college in7years and also from a random sample of students who entered at the same time and did graduate within7years. You will use these data to estimate the difference in the percent's of students from rural backgrounds among dropouts and graduates.

d. Do experienced computer-game players earn higher scores when they play with someone present to cheer them on or when they play alone? Fifty teenagers with experience playing a particular computer game have volunteered for a study. We randomly assign25 of them to play the game alone and the other25to play the game with a supporter present. Each player’s score is recorded.

A researcher wants to determine whether or not a 5-week crash diet is effective over a long period of time. A random sample of 15five-week crash dieters is selected. Each person’s weight (in pounds) is recorded before starting the diet and 1year after it is concluded. Do the data provide convincing evidence that 5-week crash dieters weigh less, on average, 1year after finishing the diet?

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Let X represent the outcome when a fair six-sided die is rolled. For this random variable, μX=3.5and σX=1.71. If the die is rolled 100 times, what is the approximate probability that the sum is at least 375?

a. 0.0000

b.0.0017

c.0.0721

d.0.4420

e.0.9279

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