Chapter 11, Problem 6CR

Before you solve Problems 6-10, first classify the problem as one of the following:

Chi-square test of independence or homogeneity

Chi-square goodness of fit

Chi-square for testing ${\sigma }^2\text{ or }\sigma$

Then in each of the problems when a test is to be performed do the following:

(i) Give the value of the level of significance. State the null and alternate hypotheses.

(ii) Find the sample test statistic.

(iii) Find or estimate the P-value of the sample test statistic.

(iv) Conclude the test.

(v) Interpret the conclusion in the context of the application.

Education: Exams Professor Fair believes that extra time does not improve grades on exams. He randomly divided a group of 300 students into two groups and gave them all the same test. One group had exactly 1 hour in which to finish the test, and the other group could stay as long as desired. The results are shown in the following table. Test at the 0.01 level of significance that time to complete a test and test results are independent.

Time	A	B	C	F	Row Total
1 h	23	42	AS	12	142
Unlimited	17	48	85	8	158
Column Total	40	90	150	20	300