## Tuesday, May 15, 2007

### SCRIBE! ( ^.^) Introduction to Probability

Hello fellow classmates and readers! I'm Tim-Math-Y your scribe for today! Today we looked at the beginning of our new unit: Probability. We talked about things such as favourable outcomes over total possible outcomes, certain events, impossible events, sample space and other interesting things.

We started off the class by looking at this interesting question:

• There was no right or wrong answer in this exercise.
• Mr. K was looking to see what we thought of probability and why we chose each numerator or denominator.
While going over each solution that the class came up with, we found that 1/(infinity) is pretty much equal to zero since it comes so close to zero.

• Here we find that 4/9 (0.444 repeating) + 5/9 (0.555 repeating) = 9/9 (1)
• It is quite interesting to see that these two repeating numbers added together gives us the value of 1.
• What we were trying to get to here was the fact that if a number comes so close to another number, we can assume that it takes that form (Ex. 1/infinity = 0)
Next we took a look at the meanings of probability and it's characteristics, including sample space.

• Notice that the "Compound Event" examples are involved in one of our last units, Counting. Specifically, the Fundamentals of Counting.
Next we observe carefully more characteristics of a probability.

• The slides today are quite self explanatory.
Next we looked at some examples of probability.

Next we looked at examples that involved finding the sample spaces.

• To find the sample space of the problem, we find the total possible outcomes either through a tree diagram or a chart/table.
• We are usually only asked this when there aren't a large number of possibilities (will be too much work)
Now we look at more examples:

• To find the probability, we divide the total number of favorable outcomes by the total number of possible outcomes.
Now we look at a really hard example:

• This is one of the attempts of solving question 1a, by one of our fellow students, John
Running out of class time, Mr. K steps in to give us the solution:

• Remember that making mistakes benefits the class in learning*
• Mr. K makes a chart with the times the bus will arrive at the top and the times of the train will arrive on the left.
• Doing this, we find the total number of ordered pairs: also known as the sample space :)

Well that was all for today guys. I know it isn't as flashy and isn't that long or awesomeness to the max but yeah, I was sidetracked a lot today haha.

Well, that wasn't too bad. Most of it was self explanatory.

Tomorrows scribe is... hmmmm...

Grey-M..

Sorry, didn't know who to pick, and it's almost SAMS BDAY HAHAH!