Math Relearning/Progressions/6-8 Statistics and Probability

These are my comments on the Common Core Math Progressions document Statistics & Probability: Grades 6-8 (PDF).

Statistics and probability aren't the most scintillating topics to me, but they're extremely important for most of the non-math subjects that do interest me.

Overview
"random sampling, a probabilistic concept" - I usually think of probability and statistics as two sides of a coin, but I'm sure that isn't their real relationship, since I'm ignorant about them, so it'll be good to learn that. So far I see that statistics depends on probability for random sampling.

Grade 6
"interquartile range" - This is all more than I remember learning about statistics in school. And even at the time I noticed that they never seemed to teach us probability. It's like they changed the curriculum and our class ended up skipping it.

Grade 7
"Chance processes and probability models" - Something I've always wondered is how probability works. It seems like magic to me.

"structure is known" -> probability; "structure is unknown" -> statistics - What a concise and informative comparison!

"'What proportion ...'" - Is this using proportion in the same sense as in the ratio progression?

"taking a sample of 50 chips" - I'd probably get tired of this exercise quickly, since it seems tedious and I wouldn't immediately see the point. Asking myself how one would normally do the real task in the real world (e.g., surveying a bunch of people) might help me appreciate the purpose and also the ease of doing a simulation.

"Why are sample sizes in public opinion polls" - If this was the point of the exercise, I'd like to have it spelled out at the beginning. I'll look ahead for things like that when I'm going through the curriculum. Keeping the goals in mind helps me pay attention to the right things while I'm working.

"some knowledge of the amount of variation to expect" - At this point I got distracted imagining how I would teach people about variation and why they'd need to know it.