Discussion:
Q1. Describe what is measured by the estimated standard error I the bottom of the independent -measures t statistics?
Q2. Harris, Schoen, and Hensley (1992) conducted a research study showing how cultural experiences can influence memory. They presented participants with two different versions of stories. One version contained facts or elements that were consistent with a U.S. culture and the second version contained materials consistent with a Mexican culture. The results showed that the participants tended to make errors for the information that was not consistent with their own culture. Specifically, participants from Mexico either forgot or distorted information that was unique to U>S> culture and participants from the United States forgot to or distorted information that unique to Mexican culture. The following data represents results similar to those obtained by Harris, Schoen and Hensley. Is there a significant difference between the two groups? Use a two- tailed test with α = .05
Number of Error Recalling the Mexican Story
n = 20 n = 20
M = 4.1 M= 6.9
SS = 180 SS = 200
Q3. Steven Schmidt (1994) conducted a series of experiments examining the effects of humor on memory. In one study, participants were given a mix of humorous
in addition, non-humorous sentences significantly more humorous sentences were recalled. However, Schmidt argued that the humorous sentences were not necessarily easier to remember, they were simply preferred when participants had a choice between two types of sentences. T tests this argument he switched to an independent -measures designed in which one group got a set of exclusively no humorous sentences. The following data are similar tit he results from the independent -measures study.
Humorous Sentences Nonhumorous Sentences
4 5 2 4 6 3 5 3
6 7 6 6 3 4 2 6
2 5 4 3 4 3 4 4
3 3 5 3 5 2 6 4
A Researcher conducted an independent- measures research study and obtain t= 2.070 with df = 28.
a. How many individuals participants in the entire research study?
b. Using a two -tailed test with α = .05, is there a significant difference between the two treatment condition?
c. Compute r2 to measure the percentage of variance accounted by the treatment effect.
Q4. A researcher conducts an experiment comparing two-treatment condition and obtains data with 10 scores for each treatment condition.
a. If the researcher used an independent-measure designed, how many subjects participated in the experiment?
b. If the researcher used a repeated - measure design how many subjects participated in the experiment.
c. If the researcher used a matched -subjects design, how many subjects participated in the experiment?
Q5. Research has shown that losing even one night's sleep can have significant effects on performances of complex tasks such as problem solving (linde & Bergstroem, 1992). To demonstrate this phenomenon a sample of n = 25 college students was given a problem -solving task at noon on one day and again at noon on the following day. The student was not permitted any sleep between the two tests. For each student, the difference between the first and second score was recorded. For this sample the students averaged Md= 4.7 points better on the first test with a variance of s2 = 64 for the difference scores.
a. Do the data indicate a significant change in problem-solving ability? Use a two-tailed test with α =.
b. Compare an estimated Cohen has to measure the size of the effect.
Q6. A researcher studies the effect of a drug (MAO inhibitor) on the number of nightmares occurring in veterans with post- traumatic stress disorder (PTSD). A sample of PTSD client s records each incidents of a nightmare for I month, and they continue to report each occurrence of a nightmare. For the following Hypothetical dtat, determine whether the MSO inhibitor significance and one-tailed test.
Number of Nightmares
1 month before treatment 1month During treatment
6 1
10 2
3 0
5 5
7 2