Refer to the stock you selected in Module 1. Using the same downloaded data, build a 95 percent confidence interval for the daily stock volume using your downloaded data. What does this confidence interval mean?

Why might dedecision-makerse interested in such an interval?

 

Confidence Interval for a Population Proportion From a sample proportion, we can calculate the standard deviation of the sampling distribution (the standard error of the estimate), and use the standardized normal distribution to get a z multiple, using the Excel function NORMSINV. The margin of error is the z multiple times the standard error, and it is how far the confidence interval extends on each side of the point estimate. Input Variables -- Sample Proportion (p-bar) 0.45