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Chapter 1: Q 1.12 (page 23)

1.12Determine the type of sampling used (simple random, stratified, systematic, cluster, or convenience). A high school principal polls 50freshmen, 50sophomores, 50juniors, and 50seniors regarding policy changes for after-school activities.

Short Answer

Expert verified

To determine the type of sampling method used

Step by step solution

01

Step 1: Given Information 

A high school principal polls50freshmen, 50sophomores, 50juniors, and50seniors regarding policy changes for after-school activities.

02

Explanation

The population is comprised of all the students at the school. This includes students in different classes. Strata are divided into classes. Students from different classes make up the entire population, which is heterogeneous. Because there is only one type of student in each stratum, each stratum is homogeneous. Thus, freshmen are in one strata, sophomores in another, and so on. Fifty students are selected from each stratum to constitute the final sample. Again, the final sample is heterogeneous, so it represents the population as a whole. This method is called stratified sampling.

03

Final answer 

The final sample is heterogenous and thus represents the total population. This method is described as stratified sampling.

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Most popular questions from this chapter

1.21 You are concerned about the effects of texting on driving performance. Design a study to test the response time

of drivers while texting and while driving only. How many seconds does it take for a driver to respond when a leading

car hits the brakes?

a. Describe the explanatory and response variables in the study.

b. What are the treatments?

c. What should you consider when selecting participants?

d. Your research partner wants to divide participants randomly into two groups: one to drive without distraction and

one to text and drive simultaneously. Is this a good idea? Why or why not?

e. Identify any lurking variables that could interfere with this study.

f. How can blinding be used in this study?

YouPolls is a website that allows anyone to create and respond to polls. One question posted April 15asks:

“Do you feel happy paying your taxes when members of the Obama administration are allowed to ignore their tax liabilities?”[5]

As of April 25,11people responded to this question. Each participant answered “NO!”

Which of the potential problems with samples discussed in this module could explain this connection?

For the following four exercises, determine the type of sampling used (simple random, stratified, systematic, cluster, or convenience).

A computer generates 100 random numbers, and 100 people whose names correspond with the numbers on the list are chosen.

Use the following information to answer the next seven exercises: Studies are often done by pharmaceutical companies to determine the effectiveness of a treatment program. Suppose that a new AIDS antibody drug is currently under study. It is given to patients once the AIDS symptoms have revealed themselves. Of interest is the average (mean) length of time in months patients live once starting the treatment. Two researchers each follow a different set of 40 AIDS patients from the start of treatment until their deaths. The following data (in months) are collected.

Researcher A: 3; 4; 11; 15; 16; 17; 22; 44; 37; 16; 14; 24; 25; 15; 26; 27; 33; 29; 35; 44; 13; 21; 22; 10; 12; 8; 40; 32; 26; 27; 31; 34; 29; 17; 8; 24; 18; 47; 33; 34

Researcher B: 3; 14; 11; 5; 16; 17; 28; 41; 31; 18; 14; 14; 26; 25; 21; 22; 31; 2; 35; 44; 23; 21; 21; 16; 12; 18; 41; 22; 16; 25; 33; 34; 29; 13; 18; 24; 23; 42; 33; 29

Suggest at least two methods the researchers might use to gather random data.

A “random survey” was conducted of 3,274people of the “microprocessor generation” (people born since 1971, the year the microprocessor was invented). It was reported that 48% of those individuals surveyed stated that if they had $2,000to spend, they would use it for computer equipment. Also, 66%of those surveyed considered themselves relatively savvy computer users.

a. Do you consider the sample size large enough for a study of this type? Why or why not?

b. Based on your “gut feeling,” do you believe the percents accurately reflect the U.S. population for those individuals born since 1971? If not, do you think the percents of the population are actually higher or lower than the sample statistics? Why? Additional information: The survey, reported by Intel Corporation, was filled out by individuals who visited the Los Angeles Convention Center to see the Smithsonian Institute's road show called “America’s Smithsonian.”

c. With this additional information, do you feel that all demographic and ethnic groups were equally represented at the event? Why or why not?

d. With the additional information, comment on how accurately you think the sample statistics reflect the population parameters
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