Normally, I have students that know something about probability, even if it is rather rudimentary. Today, virtually no one knew anything about probability, other than possessing some misconceptions. It was good to learn that there was little or no prior knowledge about probability and also to address some misconceptions, such as if you flip a coin several times in a row and they all are heads that the probability of flipping a tail increases or that the more unlikely an event the greater the probability that it occurs in a large number of trials.
I covered some basic ideas and used a bowl full of M&Ms with 50 plain and 100 peanut M&Ms as an example. The class was told that 12% of the plain and 15% of the peanut M&Ms were orange. With this information I asked several different questions about the bowl and the probability of their occurrence. I also used the class characteristics of male and female versus those wearing shorts and those not wearing shorts.
Next class will be focused on specific probability rules, representing probabilities, and practicing their use.
Below is the outline of today's lesson, with comments enclosed in square brackets and italicized [like this].
Probability
Concepts
·
What probability rules do you know?
o
Think, pair, share
o
Run through basic concepts
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0 ≤ P(A) ≤1
§
P(A) = 0 means never happens
§
P(A) = 1 means always happens
·
How can you represent probability situations
o
Tables [used coin toss to illustrate a table]
o
Venn diagrams [used gender and wearing/not wearing shorts to illustrate]
o
Use M&M problem
·
Calculating probabilities
o
P(peanut) [discussed how calculated to bring in idea of (desirable outcomes)/(total outcomes)]
o
P(not plain)
o
P(orange and plain)
o
P(orange or plain)
o
P(orange)
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