Students Struggled With…
Describing a sampling distribution from given parameters p1 and p2. Since we spend so much time talking about significance tests where the null hypothesis is p1 – p2 = 0, students will most often say the mean of the sampling distribution is 0 even when the true values for p1 and p2 are given.
Calculating a probability that a difference in proportions would be above a given amount.
Do an example in class where it is obvious that p1 – p2 would not equal 0, like proportion of AP stats students going to college versus proportion of geometry students who are going to college.
Encourage students to always draw a picture. Once a normal curve is drawn and labeled, it is much easier for students to recognize that they should calculate a z-score and find the area above it.