PSYCH 018 Index > Difference Statistics Practice

Difference Statistics Practice

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 page 543 in the book). Use SOFA statistics to perform the appropriate test, and report the result in APA style.

Scenario 1

Researchers wanted to find out if the ability to do 3-d visualization is mostly cognitive or if there is a physical component. They gathered a group of people and tested their depth perception. The participants were classified as either high or low in their depth perception. They then had to solve twenty 3-d visualization puzzles. Each person got a score for the number of puzzles solved correctly. The data is in file http://evc-cit.info/psych018/datasets/puzzle.csv

Is there a significant difference in 3-d visualization skill between the low and high depth perception groups? (Note: this is not an experiment. Just because it isn’t an experiment does not mean that it is not worth doing.)

Scenario 2

A group of students with no music training was shown a video of Bartók’s opera “Bluebeard’s Castle.” Before the video, half of the students read a synopsis of the plot. The other half read a short biography about Bartók. After the video, the students were asked to fill in a survey of how much they enjoyed various aspects of the performance. The total gave their overall rating of the opera.

Is there a difference in the priming effect of the two readings? That is, will an emotional priming (connection with the composer) be more or less powerful than a rational priming (familiarity with the plot)? The data is in file http://evc-cit.info/psych018/datasets/opera.csv

Scenario 3

Participants were told that they were doing a marketing survey. Half of the participants went into a room with natural sunlight and ate a breakfast bar in a package labeled “Test Product A.” They then went to a room with artificial lighting that had a distinct yellow cast and ate an identical breakfast bar in a package labeled “Test Product B.” After eating each bar, they judged the bar on its appearance, taste, and texture. Each attribute was rated on a scale of 1 to 4, with 1 being the lowest rating and 4 being the highest rating. The other half of the participants went through the same process except that they were in the artificial lighting first and the natural sunlight second. (This was done to counterbalance the experiment and eliminate order effects.) The data is in file http://evc-cit.info/psych018/datasets/taste.csv

Is there a significant difference in perceived quality between the two lighting conditions?