# Ch 5 Exercises Solutions

Topics: Randomness, Sampling, Simple random sample Pages: 23 (8101 words) Published: May 10, 2012
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AP Statistics Solutions to Packet 5
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Producing Data Designing Samples Designing Experiments Simulating Experiments X X X X X X X X X X X X X

HW #29 1 – 3, 5 - 7 5.1 FUNDING FOR DAY CARE A sociologist wants to know the opinions of employed adult women about government funding for day care. She obtains a list of the 520 members of a local business and professional women’s club and mails a questionnaire to 100 of these women selected at random. Only 48 questionnaires are returned. What is the population in this study? What is the sample? The population is employed adult women, the sample is the 48 club members who returned the survey.

5.2 WHAT IS THE POPULATION? For each of the following sampling situations identify the population as exactly as possible. That is, say what kind of individuals the population consists of and say exactly which individuals fall in the population. If the information given is not complete, complete the description of the population in a reasonable way. (a) Each week, the Gallup Poll questions a sample of about 1500 adult U. S. residents to determine national opinion on a wide variety of issues. An individual is a person; the population is all adult U.S. residents. (b) The 2000 census tried to gather basic information from every household in the United States. But a “long form” requesting much additional information was sent to a sample of about 17% of households. An individual is a household; the population is all U.S. households. (c) A machinery manufacturer purchases voltage regulators from a supplier. There are reports that variation in the output voltage of the regulators is affecting the performance of the finished products. To assess the quality of the supplier’s production, the manufacturer sends a sample of 5 regulators from the last shipment to a laboratory for study. An individual is a voltage regulator; the population is all the regulators in the last shipment.

5.3 TEACHING READING An educator wants to compare the effectiveness of computer software that teaches reading with that of a standard reading curriculum. He tests the reading ability of each student in a class of fourth graders, then divides them into two groups. One group uses the computer regularly while the other studies a standard curriculum. At the end of the year, he retests all the students and compares the increase in reading ability in the two groups. Is this an experiment? Why or why not? What are the explanatory and response variables? This is an experiment: A treatment is imposed. The explanatory variable is the teaching method (computer assisted or standard), and the response variable is the increase in reading ability based on the pre- and posttests.

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5.5 ALCOHOL AND HEART ATTACKS Many studies have found that people who drink alcohol in moderation have lower risk of heart attacks that either nondrinkers or heavy drinkers. Does alcohol consumption also improve survival after a heart attack? One study followed 1913 people who were hospitalized after severe heart attacks. In the year before their heart attack, 47% of these people did not drink, 36% drank moderately, and 17% drank heavily. After four years, fewer of the moderate drinkers had died. Is this an observational study or an experiment? What are the explanatory and response variables? Observational. The researcher did not attempt to change the amount that people drank. The explanatory variable is alcohol consumption. The response variable is survival after 4 years.

5.6 ARE ANESTHETICS SAFE? The National Halothane Study was a major investigation of the safety of anesthetics used in surgery. Records of over 850,000 operations performed in 34 major hospitals showed the following death rates for four common anesthetics: Anesthetic: Death Rate: A 1.7% B 1.7% C 3.4% D 1.9%

There is a clear association between the anesthetic used and the death rate of patients. Anesthetic C appears to be dangerous. (a)...

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