Lesson #3‘s main idea is for the students to understand random sampling variation. This lesson gives the students a chance to recall how to find the MAD and what the MAD represents in a data set. From there the students learn about random sampling from looking at two samples, women and men, out of a whole population of people. They will see that the mean may vary within a random sample of the same population, but usually no more than one MAD above and one MAD below the previous mean. I would rate this lesson a 4 with its alignment of the GAISE Report because the main ideas are from there but the lesson is explained a tad differently than this report.