PSYCH 018 Index > Difference Statistics Assignment

Difference Statistics Assignment

For each of the following scenarios, determine the level of measurement and whether it uses a repeated measures or independent samples design. This will determine which statistical test you need to use (see this PDF). Use SOFA statistics to perform the appropriate test, and report the result in APA style.

Note: If a probability value is greater than .001, report it exactly, without a zero before the decimal point. (p = .43; p = .02). If a probability value is less than .001, report it using a less-than sign (p < .001)

Scenario 1

Participants of both genders were asked to rate how much they want commitment in a relationship, with 0 being “none at all” and 10 being “absolutely essential.” The results are in file http://evc-cit.info/psych018/datasets/commit.csv. Is there a significant difference in the ratings between genders?

Scenario 2

Participants were divided into two groups. The first group saw a one-hour video on how to create an origami crane. The second group had a one-hour live presentation on how to create an origami crane. Participants were then given one hour to make as many cranes as they could. Their productivity was measured by the number of cranes they produced in that hour. The results are in file http://evc-cit.info/psych018/datasets/cranes.csv Is there a significant difference in productivity between the groups?

Scenario 3

Participants were asked to listen to a recorded five-minute speech over a set of headphones while a video of the person giving the speech was played on a screen directly in front of them. After listening to the speech, they rated the speech on how well they enjoyed it (1=not at all, 10=completely). They were also asked to listen to another recorded five-minute speech by the same person over a set of headphones in a room with no video and rate it on the same scale. [These two conditions were randomly counterbalanced.] The results are in file http://evc-cit.info/psych018/datasets/speech.csv Is there a signifcant difference in perceived enjoyment depending upon presence or absence of video?

Scenario 4

Participants had their pulse rate measured before viewing a horror movie and afterwards. (This was taken to be a measure of their level of anxiety.) The results are in file http://evc-cit.info/psych018/datasets/pulserate.csv Calculate the appropriate statistics for each of these three sub-parts of the scenario:

  1. Is there a significant difference based on gender in pulse rate before the movie?
  2. Is there a significant difference based on gender in pulse rate after the movie?
  3. Is there a significant overall difference in pulse rate before and after?

Note: You will need to do a separate significance test for each of these three parts. Write the results for each one as a separate paragraph. Do not try to combine them all into one paragraph. So, you will do three significance tests and write up three separate paragraphs.

When You Finish

Name your file in the form diff_stats####.docx (or .odt if you are using LibreOffice), where #### is your four-digit number. Then upload the file to Moodle.