1. An experiment is conducted to test the claim that James Bond can taste the
difference between a Martini that is shaken and one that is stirred. What is the
null hypothesis?
(relevant section)

2. The following explanation is incorrect. What three words should be added to make
it correct? (relevant section)

The probability value is the probability of obtaining a statistic as different from the parameter specified in the null hypothesis as the statistic obtained in the experiment. The probability value is computed assuming that the null hypothesis is true.

3. Why do experimenters test hypotheses they think are false? (relevant section)

4. State the null hypothesis for:

An experiment testing whether echinacea decreases the
length of colds.

A correlational study on the relationship between brain size
and intelligence.

An investigation of whether a self-proclaimed
psychic can predict the outcome of a coin flip.

A study comparing a drug with a placebo on the amount of pain relief. (A one-tailed test was used.) (relevant section & relevant section)

5. Assume the null hypothesis is that µ = 50 and that the graph shown below is the sampling distribution of the mean (M). Would a sample value of M= 60 be significant in a two-tailed test at the .05 level? Roughly what value of M would be needed to be significant? (relevant section & relevant section)

6. A researcher develops a new theory that predicts that vegetarians will have more
of a particular vitamin in their blood than non-vegetarians. An experiment is
conducted and vegetarians do have more of the vitamin, but the difference is not
significant. The probability value is 0.13. Should the experimenter's confidence
in the theory increase, decrease, or stay the same?
(relevant section)

7. A researcher hypothesizes that the lowering in cholesterol associated with
weight loss is really due to exercise. To test this, the researcher carefully
controls for exercise while comparing the cholesterol levels of a group of
subjects who lose weight by dieting with a control group that does not diet. The
difference between groups in cholesterol is not significant. Can the researcher
claim that weight loss has no effect? (relevant section)

8. A significance test is performed and p = .20. Why can't the experimenter claim
that the probability that the null hypothesis is true is .20? (relevant section, relevant section & relevant section)

9. For a drug to be approved by the FDA, the drug must be shown to be safe and
effective. If the drug is significantly more effective than a placebo, then the
drug is deemed effective. What do you know about the effectiveness of a drug
once it has been approved by the FDA (assuming that there has not been a Type I
error)? (relevant section)

10. When is it valid to use a one-tailed test? What is the advantage of a one-tailed
test? Give an example of a null hypothesis that would be tested by a one-tailed
test. (relevant section)

11. Distinguish between probability value and significance level. (relevant section)

12. Suppose a study was conducted on the effectiveness of a class on "How to take tests." The SAT scores of an experimental group and a control group were compared. (There were 100 subjects in each group.) The mean score of the experimental group was 503 and the mean score of the control group was 499. The difference between means was found to be significant, p = .037. What do you conclude about the effectiveness of the class? (relevant section & relevant section)

13. Is it more conservative to use an alpha level of .01 or an alpha level of .05? Would beta be
higher for an alpha of .05 or for an alpha of .01? (relevant section)

14. Why is "Ho: "M1 = M2" not a proper null hypothesis? (relevant section)

15. An experimenter expects an effect to come out in a certain direction. Is this
sufficient basis for using a one-tailed test? Why or why not? (relevant section)

17. A two-tailed probability is .03. What is the one-tailed probability if the
effect were in the specified direction? What would it be if the effect were in
the other direction? (relevant section)

18. You choose an alpha level of .01 and then analyze your data. (a) What is the probability that you will make a Type I error given that the null hypothesis is true? (b) What is the probability that you will make a Type I error given that the null hypothesis is false? (relevant section)