Question

A teacher claims the median grade for a certain test is 72. A sample of 25 students had the following grades. Check the teacher's claim at the .01 level.

68 52 76 92

96 72 81 91

61 94 74 72

42 87 72 69

78 85 73 81

52 86 73 78 75

Null hypothesis?

alternative hypothesis?

n?

critical value?

statistical test?

test value?

decision?

Answer choices:

A. 22

B. sign

C. median ≠ 72

D. median = 72

E. 4 F. 5 G. 6

H. reject the null hypothesis

I. do not reject the null hypothesis

Answer 1

The null and alternative hypothesis is, H:M = 72 H:M072 Level of significance, a = 0.01 No of values n=25 No of values below the median (+ve signs)= 6 No of values equal to median=3 No. of values above the median (-ve signs) = 16 The test statistic is smaller no of values below the median. That is, 6 Critical value: Using the sign test table, the critical value at 0.01 level of significance for atwo tailed test is, 6 Since the test statistic value greater than or equal to critical value, so we fail to reject the null hypothesis Conclusion: Do not reject the null hypothesis