Choosing the Appropriate Inference Procedure — Quiz
Question 1 • Statistics
A company that sells hair-care products claims that a product that combines shampoo and conditioner works better than a shampoo and conditioner used separately. A researcher recruits 60 volunteers and pairs them according to age, hair color, and hair type. For each pair, the researcher flips a coin to determine which volunteers will use the shampoo/conditioner combination and which ones will use the separate shampoo and conditioner. After using the products for one month, the subjects are asked to rate their satisfaction with the hair products on a scale of 1 – 10 ( 1 is equal to highly dissatisfied and 10 is equal to highly satisfied). The mean difference in satisfaction ratings open paren Combined minus Separate close paren is calculated. What is the appropriate procedure for testing the company’s claim?
Answer
A
one-sample t - test for μdiff
B
one-sample t -test for mu
C
one-sample z - test for p
D
two-sample t - test for mu sub c minus mu sub s
Explanation
The volunteers are matched in pairs, and within each pair one person uses the combined product while the other uses the separate products. This is a matched-pairs design, so calculate each pair’s satisfaction-rating difference (Combined minus Separate) and test whether the mean of those differences is greater than 0 using a one-sample t-test for μdiff. The correct choice is “one-sample t-test for μdiff.”
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