We spent a lot of time debating whether or not to quiz after lesson 6.3 or 6.4.  It is logical to keep lesson 6.3 with lesson 6.4 because sample counts and sample proportions are very similar.  However, we opted to assess 6.4 on the second quiz.  Sampling distributions are a new idea for students so we liked taking a little break after 6.3 to let the ideas sink in.  Also, lesson 6.4 will introduce new formulas and we didn’t want students mixing up the formulas when the concepts were still so fresh.

Students struggled the most with the idea of an unbiased estimator.  They tend to think that if a sampling distribution is normal then it must be unbiased or vice versa, if the distribution is skewed it must be biased.  Make sure to emphasize that bias means it consistently under- or over-estimates.