1. In an independent samples design, the null hypothesis is that a. the populati
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Question
1. In an independent samples design, the null hypothesis is that
a. the population mean of one group is equal to that of a second group;
b. the population mean of one group is larger or smaller than that of a second group;
c. the sample mean of one group is equal to that of a second group;
d. the sample mean of one group is larger or smaller than that of a second group.
2. "The difference between the two ____ means is zero" is a statement of the null hypothesis.
a. sample;
b. population;
c. sample or population;
d. none of the descriptive alternatives are correct.
3. Drugs used in treating schizophrenia all block the reception of dopamine by neurons. This fact led to the idea that schizophrenia occurs when too much dopamine is produced. Suppose the following data on dopamine production were obtained.
Schizophrenics
Control Group
42
33
31
27
29
18
The study described above is an example of
a. an independent-samples design;
b. a paired-samples design;
c.comparing a sample mean to a known population mean;
d. unknown; more information is required in order to decide.
4.Type A people (M= 20) were compared to Type B (M= 10) for productivity and a t value of 2.06 was obtained. With 14 A's and
a. 24 B's, the two groups are not significantly different;
b. 10 B's, the A's are significantly more productive;
c. both of the descriptive alternatives are correct;
d. neither of the descriptive alternatives is correct.
5. Null hypothesis statistical testing (NHST) allows an experimenter to conclude that the null hypothesis is
a. probably false;
b. probably true;
c. both of the descriptive alternatives are correct;
d. neither of the descriptive alternatives is correct.
6.With an acknowledgment to Sesame Street, "Which of these things is not like the others, which of these things doesn't belong?"
a. repeated measures;
b. natural pairs;
c. independent samples;
d. matched pairs.
7. "There is no difference in the two populations" is a statement of
a. the null hypothesis;
b. a one-tailed alternative hypothesis;
c. a two-tailed alternative hypothesis;
8. A student conducted a before and after study on college statistics students to see if the course improved ability to reason. In a later study, she used a mother-daughter sample to assess generational differences in attitudes toward abortion. Her two designs are
a. paired, paired;
b. paired, independent;
c. independent, independent;
d. independent, paired.
9. For a two-sample t test, an effect size that qualifies as large is
a. 0.05;
b. 0.20;
c. 0.80;
d. all of the descriptive alternatives are correct;
e.none of the descriptive alternatives are correct.
10. Thirteen volunteers weighted themselves before and after a two day fast is what specific type of a design?
a. Matched
b. Repeated measures
c. Natural
d. Independent sampling
Schizophrenics
Control Group
42
33
31
27
29
18
Explanation / Answer
1.
a. the population mean of one group is equal to that of a second group;
2.
b. population;
3.
b. a paired-samples design;
4.
d. neither of the descriptive alternatives is correct.
for option a, df = 14+24 -2 = 36, the p-value for t = 2.06 is 0.02334192
For two-tail, p-value = 2 * 0.02334192 = 0.04668384 which is less than 0.05.
So, we reject the null hypothesis and the two groups are significantly different;
for option b, df = 14+10 -2 = 22, the p-value for t = 2.06 is 0.02571089
For two-tail, p-value = 2 * 0.02571089 = 0.05142178 which is greater than 0.05.
So, we fail to reject the null hypothesis and the two groups are not significantly different;
So, both a and b options are incorrect.
5.
a. probably false;
6.
b. natural pairs;
7.
a. the null hypothesis;
8.
a. paired, paired;
9.
c. 0.80;
10.
b. Repeated measures
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