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Chapter 11: Q. 60 (page 759)

Cocaine addicts need cocaine to feel any pleasure, so perhaps giving them an antidepressant drug will help. A 3-year study with 72chronic cocaine users compared an antidepressant drug called desipramine with lithium (a standard drug to treat cocaine addiction) and a placebo. One-third of the subjects were randomly assigned to receive each treatment. At the end of the study, researchers recorded whether or not the subjects relapsed. Which of the following conditions must be satisfied to perform the appropriate chi-square test using the data from this study?

I. The population distribution is approximately Normal.

II. The treatments were randomly assigned.

III. The observed counts are all at least 5.

a. I only

b. II only

c. III only

d. II and III

e. I, II, and III

Short Answer

Expert verified

Option(b) is correct because only condition II. must be satisfied.

Step by step solution

01

Step  1 : Given information

We have to select which option is correct.

02

Simplification

Thechisquaretesthasthreeconditions:randomness,independence,andlargecounts.
The volunteers will be randomly assigned to a survey, satisfying the random sample criterion.
The sample size should be smaller than 10%of the total population in order to satisfy the requirement of independence. Because each survey's projected count is at least 5, the criterion of a large count will be met.

In given options, only II must be satisfied. Hence, b is correct.

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Most popular questions from this chapter

The National Longitudinal Study of Adolescent Health interviewed a random sample of 4877teens (grades 7to 12). One question asked, 鈥淲hat do you think are the chances you will be married in the next 10years?鈥� Here is a two-way table of the responses by gender:

Which of the following is the expected count of females who respond 鈥淎lmost certain鈥�?

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One group took a four-month stress management program, another underwent a four-month exercise program, and the third received usual heart care from their personal physicians. In the next three years, only 3of the 33people in the stress management group suffered "cardiac events," defined as a fatal or non-fatal heart attack or a surgical procedure such as a bypass or angioplasty. In the same period, 7of the 34people in the exercise group and 12out of the 40patients in usual care suffered such events.

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a. State appropriate hypotheses for performing a chi-square test for independence in this setting.

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d. What conclusion would you draw?

All current-carrying wires produce electromagnetic (EM) radiation, including the electrical wiring running into, through, and out of our homes. High-frequency EM radiation is thought to be a cause of cancer. The lower frequencies associated with household current are generally assumed to be harmless. To investigate the relationship between current configuration and type of cancer, researchers visited the addresses of a random sample of children who had died of some form of cancer (leukemia, lymphoma, or some other type) and classified the wiring configuration outside the dwelling as either a high-current configuration (HCC) or a low-current configuration (LCC). Here are the data:

Computer software was used to analyze the data. The output included the value X2=0.435

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a. There is convincing evidence of an association between wiring configuration and the chance that a child will develop some form of cancer.

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Going nuts The UR Nuts Company sells Deluxe and Premium nut mixes, both of which

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