A student participates in a Coke versus Pepsi taste test. She correctly identifies which soda is which four times out of six tries. She claims that this proves that she can reliably tell the difference between the two soft drinks. You have studied statistics and you want to determine the probability of anyone getting at least four right out of six tries just by chance alone. Which of the following would provide an accurate estimate of that probability?
a. Have the student repeat this experiment many times and calculate the percentage of time she correctly distinguishes between the brands.
b. Simulate this on the computer with a 50% chance of guessing the correct soft drink on each try and calculate the percentage of times there are four or more correct guesses out of six trials.
c. Repeat this experiment with a very large sample of people and calculate the percentage of people who make four correct guesses out of six tries.
d. All of the methods listed above would provide an accurate estimate of the probability.
Use the following information to answer questions 5-6:
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.
5. 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?