The unit Statistics, Grade 7 begins with a review lesson to remind students how to make a boxplot and a histogram and how to calculate the mean absolute deviation — all of which are 6th grade topics.
The first focus area of the unit is random sampling. Students learn that sampling methods vary and that random sampling is likely to produce an unbiased sample — a sample that represents the population well. In the lesson Using Random Sampling, students choose several random samples from a population of 100 geometric shapes, and they see first-hand that random samples can vary — even a lot. Yet if the sample size is sufficiently large, or if we have several random samples, we can be relatively confident in concluding something about the population itself. Students will also practice making inferences about populations based on several random samples.
The second major topic is comparing two populations, either directly or by using samples from the populations. Students learn to use the overall distributions and the measures of center and variability to compare two sets of data in various ways. While some of the ways in which we compare the data are informal only, all of the concepts presented are fundamental to the use of statistics in various sciences. Students also do a project where they gather data on their own from two populations and compare them.