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Chapter 11: Q. 5.2 (page 713)

Sample surveys on sensitive issues can give different results depending on how the question is asked. A University of Wisconsin study randomly divided 2400 respondents into three groups. All participants were asked if they had ever used cocaine. One group of 800 was interviewed by phone; 21% said they had used cocaine. Another 800 people were asked the question in a one-on-one personal interview; 25% said 鈥淵es.鈥� The remaining 800 were allowed to make an anonymous written response; 28% said 鈥淵es.鈥�

2. Make a two-way table of responses about cocaine use by how the survey was administered

Short Answer

Expert verified

The two way table is :

CategoryYesNo
Direct0.210.79
One on one0.250.75
Anonymous0.280.72

Step by step solution

01

Given information

In a study, 2400 respondents into three groups. All participants were asked if they had ever used cocaine. One group of 800 was interviewed by phone; 21% said they had used cocaine. Another 800 people were asked the question in a one-on-one personal interview; 25% said 鈥淵es.鈥� The remaining 800 were allowed to make an anonymous written response; 28% said 鈥淵es.鈥�

02

Solution

We need to test the hypothesis that:

H0:p1=p2=p3

Against the alternative

H0:p1鈮�p2鈮�p3

where piis the proportion of people who take consume cocain in ithprocess.

The following is a two-way table for cocain consumers obtained using different methods :

CategoryYesNo
Direct0.210.79
One on one0.250.75
Anonymous0.280.72

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Most popular questions from this chapter

Biologists wish to mate pairs of fruit flies having genetic makeup RrCc, indicating that each has one dominant gene (R) and one recessive gene (r) for eye color, along with one dominant (C) and one recessive (c) gene for wing type. Each offspring will receive one gene for each of the two traits from each parent. The following Punnett square shows the possible combinations of genes received by the offspring:

Any offspring receiving an R gene will have red eyes, and any offspring receiving a C gene will have straight wings. So based on this Punnett square, the biologists predict a ratio of 9 red-eyed, straight-winged (x):3 red-eyed, curly-winged (y):3 white-eyed, straight-winged (z):1 white-eyed, curly-winged (w) offspring. To test their hypothesis about the distribution of offspring, the biologists mate a random sample of pairs of fruit flies. Of 200 offspring, 99 had red eyes and straight wings, 42 had red eyes and curly wings, 49 had white eyes and straight wings, and 10 had white eyes and curly wings. Do these data differ significantly from what the biologists have predicted? Carry out a test at the A  0.01 significance level

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Explain carefully why it would not be appropriate to perform a chi-square goodness-of-铿乼 test using these data.

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