Lab 6

Your task is to consider the following: Does using a cell phone while driving make an accident more likely?
Researchers compared telephone company and police records to find 699 people who had cell phones and were also involved in an auto accident. Using phone billing records, they compared cell phone use in the period of the accident with cell phone use the same period on a previous day.
Result: the risk of an accident was 4 times higher when using a cell phone.

1) What kind of study was this?
2) What is the explanatory variable?
3) The researcher also recorded the manufacturer of each subject's cell phone (Motorola, Nokia, etc). What kind of variable is this information and what scale of measurement is used?
4) Give an example of a potential confounding variable that might affect the results of this study.

Does coaching raise SAT scores?
Because many students score higher on a second try even without coaching, a study looked at a simple random sample of 4,200 students who took the SAT twice. Of these, 500 had taken coaching courses between their two attempts at the SAT. The study compared the average increase in scores (out of the total possible score of 1600) for students who were coached with the average increase for studetns who were not coached.

1) Is this an experiment? Why or why not?
2) Does this study demonstrate that coaching causes a greater increase in SAT scores?

Use of nicotine replacement therapies and the antidepressant bupropion helps people stop smoking. We conducted a double-blind, placebo-controlled comparison of sustained-release bupropion (244 subjects), a nicotine patch (244 subjects), bupropion and a nicotine patch (245 subjects), and placebo (160 subjects) for smoking cessation.
Results. The abstinence rates at 12 months were 15.6 percent in the placebo group, as compared with 16.4 percent in the nicotine patch group, 30.3 percent in the bupropion group, and 35.5 percent in the group given bupropion and the nicotine patch.

1) How many conditions were there in this experiment?
2) What was the response variable in this experiment?
3) What was the purpose of giving one group a placebo?

Do doctors in managed care plans give less charity care? Researchers chose 60 communities at random, then chose doctors at random in each community. In all, they interviewed 10,881 doctors. Overall, 77.3% of the doctors said they had given some care free or at reduced rates because of the patient's financial need in the month before the interview. Doctors who received at least 85% of their practice income from managed care plans were significantly less likely than other doctors to provide charity care.

1) What kind of design (e.g., experiment, observational, etc.) does this study use?
2) Is 77.3% a parameter or a statistic? What does that mean?
3) Some doctors who did not give any charity care may say that they did. If so, the study suffers from some problems. What are some of these problems?

Students in a large statistics class were randomly divided into two groups. The first group took the midterm exam with soft music playing in the background while the second group took the exam with no music playing. The scores of the two groups on the exam were compared.

1) What is the instrument in this experiment?
2) What is the response variable in this experiment?
3) What is the explanatory variable in this experiment?
4) What kind of design was used in this experiment?
5) What could be done to improve this experiment?

A national sample survey interviewed 3,800 people aged 18 and older nationwide by telephone. One question asked was whether they agreed with this statement: "Some people say we should have a third major political party in this country in addition to the Democrats and Republicans."

1) What is the population of this study
2) 53% of the people asked agreed that we should have a third party. What is that 53% (e.g., a parameter, a statistic, a confidence interval, etc.)?

A six-sided die is rolled.
1) What is the sample space of outcomes on a single roll?
2) What is the probability of getting an even number on a single roll of the die?

Two six-sided dice are rolled.
1) What is the sample space of outcomes of a single roll of this pair of dice?
2) What is the probability of getting a 7 for the sum of the two dice?
3) What is the probability of getting a pair (the same number on each die)?

Since this is a review lab I'll provide a link to solutions to these questions.  I STONGLY advise you to try to answer them all before you check your answers.

SPSS WORK

CREATE AN SPSS FILE FOR THE FOLLOWING DATA FROM THE FIRST 8 PARTICIPANTS IN A STUDY OF DEMOGRAPHIC FACTORS POSSIBLY RELATED TO ACT SCORES.

ID#01 Age: 15 Gender: Male Children in household: 1 Parental status: Mom only ACT score: 22	ID#: 02 Age: 17 Gender: Female Children in household: 3 Parental status: Mom, dad together ACT score : 25	ID#: 03 Age: 18 Gender: Male Children in household: 2 Parental status: Mom, dad apart ACT score: 25
ID#: 04 Age: 16 Gender: Male Children in household: 4 Parental status: Mom only ACT score: 14	ID#: 05 Age: 19 Gender: Male Children in household: 2 Parental status: Mom, dad together ACT score: 15	ID#: 06 Age: 20 Gender: Female Children in household: 6 Parental status: Mom, dad together ACT score: 15
ID#: 07 Age: 18 Gender: Female Children in household: 3 Parental status: Mom, dad together ACT score: 28	ID#: 08 Age: 18 Gender: Female Children in household: 2 Parental status: Mom, dad apart ACT score: 23

Upload your SPSS .sav file to the Lab Assignment.