Question

Finally, you decide to repeat this same procedure to examine salaries among male accountants in your firm. You do not necessarily expect salaries to be larger or smaller than the average. The same large national survey of male accounts found that the average salary was $60,000 with a SD of $5,500. After sampling 55 male accountants in your organization, you find their average salary is $57,000. Use a two-tailed z-test at the 5% level of significance to determine if there is a significant difference between the male national average and male salaries in your company. 9. State alternative hypothesis 10. State null hypothesis 11. List your test statistic 12. Is this difference statistically significant?

Answer 1

Given data are sample n=55

Population mean u=$60000

Population sd σ=$ 5500

Sample mean =$ 57000

Null hypothesis H0: u=60000

alternative hypothesis Ha: u60000

α= level of significance =5%=0.05

Test statistic:-

In a z Normal distribution z= ( -u) /(σ/)

Z=(57000-60000)/(5500/)

=-3000/741.6198

= -4.0452

Decision rule:- at α=0.05 in 2 tail from z table zα/2=1.96

Reject H0 if zcal< -1.96 or zcal>1.96

Decision :- Zcal< -1.96

So reject the null hypothesis H0

Conclusion:- it is statistically significant at5% level

At 5% level there is sufficient enough evidence to support the claim that their is a significant difference between the male national average and male salaries in the company