Question

Where do CFOs get their money news? According to Robert Half International, 47% get their money news from newspapers, 15% get it from communication/colleagues, 12% get it from television, 11% from the Internet, 9% from magazines, 5% from radio, and 1% do not know. Suppose a researcher wants to test these results. She randomly samples 76 CFOs and finds that 40 of them get their money news from newspapers. Does the test show enough evidence to reject the findings of Robert Half International? Use a = .05.

Answer 1

Let = The Proportion of CFO's who make money from news papers = 40 / 76 = 0.526

Let p = The Population proportion of CFO's who make money from news papers = 0.47

1 - p = 0.53

= 0.05

(a) The Hypothesis:

H0: p 0.47

Ha: p > 0.47

This is a Right tailed Test.

The Test Statistic:

The p Value:    The p value (Right tail) for Z = 0.98, is; p value = 0.1635

The Critical Value:   The critical value (Right tail) at = 0.05, Zcritical = +1.645

The Decision Rule: If Zobserved is > Zcritical Then Reject H0.

Also If the P value is < , Then Reject H0

The Decision:   Since Z observed (0.98) is < Zcritical (1.645), We Fail to Reject H0.

Also since P value (0.1635) is > (0.05), We Fail to Reject H0.

The Conclusion:   There isn't sufficient evidence at the 95% significance level to warrant rejection of Robert Half Internationa's claim that 47% of the CFO's make their money from newspapers.