1) A learning researcher is interested in the effectiveness of her new memory enhancement program. To test this program, she has 15 students learn a list of 50 words. Memory performance is measured using a recall test. After the first test, these same students are instructed as to how to use the memory improvement program and then learn a second list of 50 different words. Memory performance is again measured with the recall test. If you wanted to test the hypothesis to see if the memory program actually improves memory, what would be the appropriate analysis? What would be the null and alternative hypotheses for this test? Would the alternative hypothesis be one-tailed (directional) or two-tailed (non- directional)? Why?
2) In the table, below, the number of correctly remembered words are listed for both tests (see #1, above). Based on these results, calculate the appropriate test for these data (assumea= .05) to determine if the memory enhancement training program produces better recall. Be sure to state the calculated and critical values of the statistic for this test. Would you reject or fail to reject the null hypothesis in this situation? Why? Show your work and include all formulas that you're using!
(see the next page for the data)
1
2
Student Score 1 Score 2
1 24 26
2 17 24
3 32 31 4 14 17 5 16 17 6 22 25 7 26 25
8 19 24
9 19 22
10 22 23
11 21 26
12 25 28
13 16 19 14 24 23
15 18 22
3) Summarize the results of this test using the "Method of Presentation" format from your textbook (what I referred to as the "M.O.P." in the video lectures). Be sure to address all three questions in your written summary (i.e., 1) Is there a relationship?; 2) What is the strength of the relationship?; 3) What is the nature of the relationship?). Also be sure to include the 95% confidence interval in your summary.
4) A study was done to evaluate the possible effects of food on mood. Twenty college students were randomly assigned to either Condition 1 (an all-carbohydrate lunch) or Condition 2 (an all-protein lunch). One hour after eating lunch, each participant rated his or her degree ofsleepiness, with higher scores indicating higher degrees of sleepiness. The researchers wanted to determine if the degree of perceived sleepiness differed as a function of the assigned food group. What would be the null and alternative hypotheses for this test? Would the alternative hypothesis be one-tailed (directional) or two-tailed (non-directional)? Why? What would be the appropriate analysis to use to test these hypotheses? Explain!
3
5) The data (ratings of perceived sleepiness based on a 0-15 scale, where
low numbers indicated low levels of sleepiness and vice versa) for the experiment outlined in #4, above, appear below:
Condition1:1 7 3 2 4 2 6 5 4 5Condition2:0 1 3 4 0 2 0 3 0 4
Calculate the appropriate test for these results (assumea= .05). Be sure to state the calculated and critical values of the statistic for this test. Would you reject or fail to reject the null hypothesis in this situation? Why? Show your work and include all formulas that you're using!
6) Summarize the results of this test using the "Method of Presentation" format from your textbook. Be sure to address all three questions in your written summary (i.e., 1) Is there a relationship?; 2) What is the strength of the relationship?; 3) What is the nature of the relationship?). Be sure to include the 95% confidence interval in your summary.
7) An experiment is done to compare the effects of three situations: Situation 1 is tested in a “no-stress,” baseline situation; Situation 2 does a mental arithmetic task; and Situation 3 participants do a mock job interview. At the end of each session, the participants self-report their anxiety on a scale that ranges from 0=no anxiety to 20=extremely high anxiety. The researcher wants to know whether, overall, anxiety levels differed across these three different situations. Each of the 21 participants was randomly assigned to one of the three stress conditions. If you wanted to test the hypothesis to see if there was any effect of the three situations on the subjects' ratings of anxiety, what would be the appropriate analysis? What would be the null and alternative hypotheses for this test? Would the alternative hypothesis be one-tailed (directional) or two-tailed (non-directional)? Why? Explain!
8) Here are the results found in the study described in #7, above (where the values indicate the ratings provided based on the 20-point rating scale):
Group
|
Anxiety Ratings
|
Situation 1
|
12
|
7
|
12
|
11
|
7
|
10
|
10
|
|
Situation 2
|
14
|
17
|
14
|
13
|
11
|
14
|
17
|
|
Situation 3
|
18
|
16
|
14
|
16
|
19
|
20
|
16
|
|
Calculate the appropriate test for this situation (assumea= .05). Be sure to state the calculated and critical values of the statistic for this test. Would you reject or fail to reject the null hypothesis in this situation? Why?Show your workand include all formulas that you're using! Be sure to summarize your calculations using the appropriate "summary table" that I described in my video lecture -- label the rows and columns of this summary table clearly.
9) Summarize the results of this test using the "Method of Presentation" format from your textbook. Be sure to address all three questions in your written summary (i.e., 1) Is there a relationship?; 2) What is the strength of the relationship?; 3) What is the nature of the relationship?). Be sure to include the 95% confidence intervals in your summary.
10) Outline, define, and explain the assumptions for the three major analyses discussed in this unit: theindependent-groups t-test, thecorrelated-groups t-test, and theone-way between-subjects ANOVA. Why are these assumptions important? How are these assumptions assessed/tested by statisticians? What do they have to do with therobustnessof a statistical test? Explain and be specific, and treat this question as an essay (i.e., write in complete sentences and be thorough)!