Question

1.       A psychopharmacologist conducted a study on the effects of the drug lithium for the treatment of depression. Twenty-seven patients were chosen whose principal problem was depression. There were 3 groups: Placebo, Low Dose (50mg) and High Dose (200mg). There were 9 patients in each group. At the end of 30 days, the patients were evaluated for their level of depression, with higher scores indicating higher levels of depression.

                Fill in the blanks with the appropriate numbers, setting alpha=.05.

Source                  SS           df            MS         F              p

Total                      _____   __

Between             143.41   __           ___        ___        ___

Within                   365.11   __           ___

2.                   Which of the following is true of between-subjects ANOVA?

   A)           Participants provide data for just one condition/level of the independent variable.

                B)            Participants contribute data to every condition/level of the independent variable.

3.            A between-subject ANOVA is similar to an independent t-test, EXCEPT _____.

   A)           that in a between-subjects ANOVA , the IV cannot have more than two levels

                B)            that in a between-subjects ANOVA, the DV cannot exceed the alpha level

                C)            that in a between-subjects ANOVA, the IV can have three or more levels

                D)           that in a t test, the DV has to be nominal

3.                   In a J=3 between-subjects ANOVA, we find that the p-value is 0.003. We therefore conclude that:

   A)           there is no statistical evidence that any group mean is different from any other

                B)            all group means are equal

                C)            all group variances are equal

                D) all group means are different

                E)            the null hypothesis should be rejected

5.            In an ANOVA with J = 5 and a total sample size of 65, using ? = 0.05, what is the critical value?

4.                   Use the following information to answer the questions (6a-6d) that come after it:

You are interested in the effect of pay on the productivity of your employees. To test this effect you set up a study. The results follow:

Source                  SS           df            MS         F              p

Total                      291.51   38

Between (Pay) 99.51     2 46.76     9.33        <.01

Within                   192.00   36           5.33

6a.          What is your null hypothesis?

A)           More pay will lower or not affect productivity.

               B)            More pay will raise or not affect productivity.

               C)            Pay will not affect productivity.

D)            None of the above

6b.          How many levels of the independent variable are in the experiment?

  A)           1

                B)            2

                C)            3

D)            None of the above

6c.          How many participants were in the study?

  A)           38

                B)            39

                C)            40

                D)           None of the above

6d.          With ?=.05, what is your decision?

  A)           Accept the null hypothesis.

                B)            Accept the alternative hypothesis.

Answer 1

2.                   Which of the following is true of between-subjects ANOVA?

B) Participants contribute data to every condition/level of the independent variable.

3.            A between-subject ANOVA is similar to an independent t-test, EXCEPT _____.

C) that in a between-subjects ANOVA, the IV can have three or more levels

3.                   In a J=3 between-subjects ANOVA, we find that the p-value is 0.003. We therefore conclude that:

E)            the null hypothesis should be rejected (since p-value<0.05)

5. In an ANOVA with J = 5 and a total sample size of 65, using ? = 0.05, what is the critical value?

Critical value=F_0.05,4,60=2.5252

6a.          What is your null hypothesis?

C) Pay will not affect productivity.

6b.          How many levels of the independent variable are in the experiment?

C) 3

6c.          How many participants were in the study?

B) 39

6d.          With ?=.05, what is your decision?

B) Accept the alternative hypothesis (since p-value<0.01)