A student interested in alternative sleep aids has heard that valerian root, melatonin and 5-htp have very few side effects and may be able to help with her recent insomnia. She decides to run a little experiment with her sorority sisters to determine which of the three makes people fall asleep the fastest. She randomly assigns her twelve sisters to one of three sleep aid groups and has each consume a similar dosage just before getting in to bed. A video camera in each room allows her to record the amount of time, in minutes it takes each sister to fall asleep. The data is below.
Valerian Root Melatonin 5- HTP
29 39 25
32 32 30
27 34 31
30 36 27
Identify the independent variable -
and the dependent variable in this study-
Then also determine how many levels (conditions) of the IV there are-
State the null hypothesis and alternative hypothesis in words-
Calculate the degrees of freedom within groups
the degrees of freedom between groups
and determine the F critical value using an alpha level of α = .05
At this point, knowing the F-test and F-critical values, what conclusion can be made
Calculate R 2and explain what the calculated value tells us regarding the effectiveness of the sleep aids.
Calculate the F c o n t r a s t post-hoc tests for each of the three sleep aid comparisons and determine the F c r i t i c a l value for the contrast (use an α= .05).
1. Valerian - Melatonin =
2. Valerian - 5htp =
3. Melatonin - 5htp =
Given the calculations of your F c o n t r a s t s in the previous question, what conclusion should one make regarding the effectiveness of the three sleep aides used in this study?