6.11 Assumptions Behind the t-test

For the following scenarios, what is the strongest argument against the validity of a t-test?

• You have a sample of 50 CEO salaries, and you want to know whether the mean salary is greater than $1 million.

• A nonprofit organization measures the percentage of students that pass an 8th grade reading test in 40 neighboring California counties. You are interested in whether the percentage of students that pass in California is over 80%

• You have survey data in which respondents assess their own opinion of corgis, with options ranging from “1 - extreme disgust” to “5 - affection so intense it threatens my career.” You want to know whether people on the average like corgis more than 3, representing neutrality.