To study the role of internal and visual cues in determining how much people eat, researchers conducted an experiment in which people are randomly assigned to drink soup from either ordinary bowls or bowls that are secretly refilled. Here are the results:
| |
Sample Size |
Mean |
Standard Deviation |
| Ordinary bowls |
27 |
11.5 oz |
6.1 oz |
|
Bowls that are secretly
refilled
|
27 |
17.7 oz |
8.4 oz |
You may assume that all conditions are met.
A 95% confidence interval comparing the two groups is (2.18, 10.22) oz. Use this interval to comment on whether there is an effect due to having the bowls secretly refilled.
If there is no evidence of an effect explain how the interval conveys that. On the other hand, if there is evidence of an effect, what is the direction of the effect, as in, which group has the higher mean consumption, and what do you estimate the true effect to be?