Determine whether the description corresponds to an observational study or an experiment:

The researcher wants to determne the difference in the academic performance of accounting students from difference school. Thus, the midterm examination result for the colleges were retrieved by researchers.The result of the test were compared and described by the researchers.

Determine whether the given description corresponds to an observational study or an experiment.

In a study of $238$ students enrolled at a university who have mental disorders, the subjects were given particular type of drugs to determine whether the drugs had an effect on their academic excellence.

Researchers conducted a study to determine whether magnets are effective in treating back pain. Pain was measured using the visual analog scale, and the results given below are among the results obtained in the study (based on data from "Bipolar Permanent Magnets for the Treatment of Chronic Lower Back Pain: A Pilot Study," by Collacott, Zimmerman, White, and Rindone, Journal of the American Medical Association). Higher scores correspond to greater pain levels.

Reduction in Pain Level After Magnet Treatment: $n=20, \bar{x}=0.49, s=0.96$

Reduction in Pain Level After Sham Treatment: $n=20, \bar{x}=0.44, s=1.4$

Is this study an experiment or an observational study? Explain.

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Zip codes

Determine whether the study depicts an observational study or an experiment. A study is conducted to determine if there is a relationship between skin cancer and hair color. The hair color of patients with skin cancer is recorded. Does the description correspond to an observational study or an experiment?
a) The study is an observational study because the researchers control one variable to determine the effect on the response variable.
b) The study is an experiment because the study examines individuals in a sample, but does not try to influence the variable of interest.
c) The study is an observational study because the study examines individuals in a sample, but does not try to influence the response variable.
d) The study is an experiment because the researchers control one variable to determine the effect on the response variable.

Determine whether the study is an experiment or an observational study, and then identify a major problem with the study. The Physicians' Health Study involved 22,071 male physicians. Based on random selections, 11,037 of them were treated with aspirin and the other 11 ,034 were given placebos. The study was stopped early because it became clear that aspirin reduced the risk of myocardial infarctions by a substanti al amount.

Order the following $r$ values in order from the weakest to the strongest linear relation:

$$r=0.90,~r=-0.68,~r=0.03,~r=-1.$$

$a) -1,~-0.68,~ 0.03,~ 0.90$.

$b) ~0.03,~ 0.90,~ -0.68,~ -1$.

$c)~0.03,~ -0.68,~0.90,~-1$.

$d)~ -1,~0 .03,~ -0.68,~0.90$.

Researchers conducted a study to determine whether magnets are effective in treating back pain, with results given below. The values represent measurements of pain using the visual analog scale. Use a 0.05 significance level to test the claim that those give n a sham treatment (similar to a placebo) have pain reductions that vary more than the pain reductions for those treated with magnets. Reduction in pain level after sham treatment: n=20, $\bar{x}=0.44$, s=1.4. Reduction in pain level after magnet treatment: n=20, $\bar{x}=0.49$, s=0.96.

Determine an article that describes a statistical study, and identify the study as observational or experimental.

Which of the following correlation coefficients indicates the strongest relationship between two variables? a. $-90$ b. $-50$ c. $+.80$ d. $+.25$

Which of the following values for a correlation coefficient indicates the strongest degree of relationship?

Identify the level of measurement of the data. Also, explain what is wrong with the given calculation.

In Data Set 5 in Appendix B, blood lead levels are represented as 1 for low, 2 for medium, and 3 for high. The average (mean) of the 121 blood lead levels is 1.53.

What is the main subject of evolutionary psychology?

Identify the level of measurement of the data. Also, explain what is wrong with the given calculation.

Data Set 15 in Appendix B lists the flight numbers of 48 different flights, and the average (mean) of those flight numbers is 11.0.