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To determine if there is a relationship between grade performance and extracurricular participation, North Carolina state conducted a study of 112 students, recording the number of students in each of three extra-curricular categories, and each of two grade categories.

Here are the results:

	Good grades	Poor grades
Low extra-curricular participation	11	2
Moderate extra-curricular participation	68	23
High extra-curricular participation	3	5

(Source: Felder, et.al., “A Study of Student Performance in an Introductory Chemical EngineeringCourse,” 1992 ASEE Annual Conference Proceedings, pp. 1516–1519.)

Which of the following facts should make you the most worried about the reliability of the results of the test in this case?

The 112 students were all students in a chemical engineering course and not a random sample from the entire student body.
Two of the six observed counts are less than 5.
Not all of the cells' contributions to the chi-squared statistic are greater than 1.
Two of the six expected counts are less than 5.

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