An organizational psychologist is hired as a consultant to a company planning to open a coffee house for college students. The company wants to know if their customers will drink more coffee if the coffee house is decorated in a Paris motif or in a San Francisco motif, so the psychologist sets up two similar rooms with the two motifs. Eight students spend an afternoon in each room, drinking all the coffee they like. The order in which they sit in the rooms is rotated so that half spend their first afternoon in the Paris room and half in the San Francisco room. The amount of coffee each participant drinks in each room is shown below. Using the .05 significance level, is there a significant difference between the numbers of cups of coffee consumed in the two rooms?
Cups of Coffee
Participant Paris San Francisco
A 8.5 8.4
B 4.3 4.6
C 2.0 1.7
D 7.8 7.3
E 7.0 7.2
F 9.1 7.4
G 3.3 3.0
H 3.5 3.5
a. Use the five steps of hypothesis testing.
b. Sketch the distributions involved.
c. Figure the effect size and find the approximate power of this study.
d. Explain the logic of what you did to a person who is familiar with hypothesis testing with a known population variance and a single sample, including understanding decision errors, effect size and power, but who knows nothing about t tests of any kind (for example, you do not need to describe the steps or logic of hypothesis testing). Be sure you explain how this problem differs from a problem with a known population variance and a single sample. Your answer should consist mainly of a thorough explanation of the characteristics of the comparison distribution and all the figuring you did to determine those characteristics.
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