The researchers from Exercise 2 want to test if the proportions of satisfied employees are the same at for-profit companies as at not-for-profit companies.
In Exercise 2
Data collected from 422 employees at non-profit organizations revealed that 377 of them were "highly satisfied." From the for-profit companies, 431 out 518 employees reported the same level of satisfaction.
a) What is the difference in the proportions of the two types of companies?
b) What is the pooled proportion of satisfied employees in both types of companies combined?
c) What is the standard error of the difference in part a?
d) What is the value of the z-statistic?
e) What do you conclude at ( = 0.05?