Losing (My) Marbles

My AP Statistics class starts Probability sometime next week (I’ve scheduled a couple days of how-to-answer-multiple-choice in there, so I’m not precisely sure when). I’m dreading it.

I think I’m less-than-great at teaching it, but I also think I come up against a lot of baggage when we hit probability. No one thinks they know z-scores. Students readily accept that I will teach them new things about scatterplots. But probability? I’ve got that down.

Probability is easy, right? We started those problems in third grade, and for whatever reason it shows up every.single.year. Marbles? Jelly beans? Candy? Socks? Shoes? Elvis’ jumpsuits? Done ’em all.

And so I take a bunch of students who “know” probability and…it all falls apart.

I suspect the breakdown happens in between the students feeling like they’ve totally got probability (marbles) and getting at the idea of a long-run frequency of something occuring. Instead of probability as “over many tosses, about half will be heads”, it becomes “you get heads half the time, because that’s just the way it is. And since I just got tails, heads is next.”

So how do I undo that? How do I help them see probability as long-run chance, and never ever a sure thing (well, unless its 0 or 1)?

Part of me thinks I should try to teach as much probability as possible without using the word “probability”. Or maybe do some exploration of different probabilities before I start formally teaching the actual content.

Part 2 is how tricky vocabulary is around probability (especially since English isn’t my students first language). Last year I did a foldable with vocab but I’m not sure how helpful that was (if at all).

Should I have the students model the same situation several ways? Generate our own data and use that?

How do you teach probability? Any ideas of where the disconnect might be? Help!!


2 responses to “Losing (My) Marbles

  1. S

    since you have a language disconnect, why not make a word wall translating some of the key terms into multiple languages? Especially if you can include pictures representing the concepts.

    We do lots of hands on things, making predictions and verifying them all the way. We do Monte Hall’s paradox, but still students don’t believe it.

    I know my students regularly perform badly on Odds, even when they can recite the definition back to you, they still bomb it on the test.

    how about announce the topic, ask for all the ideas and notions first and then explore their validity?

    Also, if you’re not reading it, check out http://mathwithbaddrawings.com/the-bear-in-the-moonlight/ he’s doing a wonderful job with writing stories to introduce these topics.

    • Mary

      Wow, thanks!

      We’ve been spending a lot of time on predicting in Algebra 1 and it would probably really help here as well. And I’ve already added Math with Bad Drawings to my reader (and your blog!) so thanks for the new reads.

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