Thursday, December 12, 2013

Working with Probability

December 5th - In our lead up to the winter break, we have been working with the concept of probability during our numeracy time. Our main objective was to help the students understand the difference between the following terms:

impossible ------- unlikely ------- possible ------- likely ------- certain

We introduced this concept by using spinners labelled with students' names. The spinners were divided into equal parts, and the students had to record the results of 100 spins. What we realized was that the results were not equal for all students. For instance, a group of 4 students would predict that each student's name would be landed on 25 times in 100 spins. What we found though was that some students' names were landed on as little as 17 times and as many as 36 times. This meant that it was more probable that the spinner would land on one student's name than that of their partners.

We explored the possible reasons for this. The students suggested that each person might be spinning it differently, or that the starting point was not the same on all spins. Others even went so far as to suggest that there might be a slight defect on the spinner itself that was causing friction in a way that affected it's ability to spin freely. These were all interesting  suggestions.

The main thing we learned was that, though it was possible for all students to have their name landed on with any given spin, it was (for some reason) more likely that one name in particular would be landed on. This allowed for a small amount of predictability for the students, which is really the basis of any study on probability. We plan to repeat this experiment using something other than spinners to see if we get similar results.