Question

A Business Week/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, 220 of 400 executives answered yes, while in a previous year survey, 192 of 400 executives had answered yes. Provide a 95% confidence interval estimate for the difference between the proportions at the two points in time.
What is your interpretation of the interval estimate?

Answer 1

Answer:

Lower limit P1 =0.001

Upper limit P2 = 0.139

We are 95% sure that the interval (0.000905, 0139) contains the difference be- tween true population proportion pi - p2

2) If a large number of samples are collected, and a confidence interval is created for each sample, 95% of these intervals will contain the difference between true population proportion P1- P2

3) Since this Cl does not contain zero, we can conclude at a-0.05 that true mear difference is not zero. Further since this Cl is entirely on the right of 0, we conclude at α = 0.025 that the true mean difference is greater than zero

Step-by-step explanation: