Just in case you were wondering, I thought I should post something that shows that I really do teach. So far all my posts have been rather non-classroomy, and I haven’t shared many teaching ideas…which was partly why I started this blog. So…

Today in prob/stats we started our unit on bi-variate data. Completely hijacking an idea from one of my new twitter friends, @druinok, I had the students work through a variety of stations requiring them to do different types of data collections. The stations were:

#1. Number of letters in your first name, Length of your hair

#2. arm span, height

#3. day of the month of your birthday, number of days remaining in the month

#4. number of seconds in the pencil sharpener, length of pencil (graph shown below)

#5. swimming space, number of blocks (to build a bug swimming pool-using blocks of some kind. Idea from “A graphing matter” by Mark Illingworth, Key Curriculum Press, c. 1995.) (graph shown below)

#6. length of the side (of a rectangle of perimeter 24), Area of rectangle

#7. Shoe size, length of your hair

What was supposed to happen: Station 5 would be perfectly linear, correlation coefficient +1; Station 2 would have high positive correlation coefficient; Station 7 would have a hint of positive correlation, although it would be due to a hidden (lurking maybe?) variable. Station 1 should have no correlation whatsoever. Station 3 and 4 would both show negative correlation, with 4 being extremely close to -1. Station 6 was thrown into the mix to give us a curved association, just for kicks.

What really happened: I was reminded once again that high school students cannot use a tape measure and cannot create very accurate graphs. Even the bug swimming pool, which required no measurement, did not turn out completely linear. (Note to self: get large sheets of graph paper next time.)

The pencil station was just annoying. Sorry to my dear neighbors who were probably trying to get their kids to concentrate on something extra difficult. (Note to self…find something quiet that will generate moderately strong negative correlation). Even more upsetting than the aggravating noise, the graph did not turn out quite as I expected. (This is why I should work through each station first…you’d think after 16 years I’d learn.) The change in the pencil length was slow. I had the kids record lengths after every 5 seconds. In reality it needed to be more like every 15 or 20 seconds.

Most of the stations went quickly, but the arm span/height and the pencil sharpening stations slowed us down.

I only had one of each station available…For my large class (26 students) I needed to have two of each and smaller groups. There just wasn’t enough work to justify teams of 3 or 4, but the space with which I had to work limited me to one of each station. (Dear school board/administration/whoever can give me money: I need to get rid of my clunky, over sized, non-group promoting desks and get tables. Thanks).

Because of my own laziness (and the desire to go to bed before midnight last night) I had to do all of the set up work for this activity this morning. Consequently, I didn’t quite have it all set up when the first class walked in. Trying to give directions while setting up the stations…not good. 4th and 5th periods were set up and ready, but we still used almost 60 minutes (out of 70) discussing the stations and collecting the data. We did not have time to do anything with it today, so tomorrow will be spent discussing the similarities and differences between the graphs and the data. We’ll then talk about direction, form, and strength. Eventually we’ll actually look at the correlation coefficients and use these stations as a starting point for that discussion.

Good things: I got to use my laminating machine. Students seemed to be engaged in the activity. Everyone was up and at least walking around. I think the kinesthetic and visual learners have some good stuff to refer back to during the rest of the unit. I didn’t stand in front of them and lecture. All in all, I guess it wasn’t too bad for the first go ’round.

Just for proof…here are the kids up and working.

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Mario Martinez (@Martimatix)

said:Thanks for blogging about this great idea. I’ll be doing a lot of chance and data this term and will consider using this activity.