1- How do you determine when to use Z vs T

2- What will happen to the Confidence Interval as the alpha level decreases? What part of the interval will be affected and how? (increase, decrease?)(PE,CV,SE,ME?)

3- What will happen to the Confidence Interval as the sample size increases? What part of the interval will be affected? (PE,CV,SE,ME?)

4-How does changing the sample size effect Z and T Critical Value?