Question

A Businessweek/Harris survey asked senior executives at large corporations their opinions about the economic outlook for the future. One question was, "Do you think that there will be an increase in the number of full-time employees at your company over the next 12 months?" In the current survey, 240 of 500 executives answered Yes, while in a previous year survey, 196 of 500 executives had answered Yes. Provide a 95% confidence interval estimate for the difference between the proportions at the two points in time (to 4 decimals).

Answer 1

Here we have to use 'Z' test for difference of proportions for calculation of confidence interval estimate for the difference between the proportions.