## December 19, 2006

### Probability

Sorry guys this came late, and I gotta sleep soon too, My net's very .. bad .. and I haven't gotten on till now, but yes .. In the morning we were given 3 questions to do on the board.

1. Find the sample space for the genders of 3 children?

2. What is the probability of 2 children in a family both being boys?

3. What is the probability of drawing a red card and then a black card out of a deck of 52 playing cards if:

a) The first card is replaced before the second is drawn?
b) The first card is not replaced before the second is drawn?

The answer to this question will have to be drawn, but it would have to be listed and these are it:
B= Boys
G= Girls

BBB
BBG
BGB
BGG
GBB
GBG
GGB
GGG

2. The answer to this question is well 1/4 because when you want something to happen you have to multiply. It would help making a diagram =).

3.a) The answer for the first one would be 1/4.
b) The answer for this would be
P(RB)= (26/52)(26/52)
which would equal 0.2549

For the last part of class we wrote a bit of definitions in out math dictionary:

Dependant events: 2 ( or more ) events are dependant if the outcome of the second event depends on what occurred in the first event.

Example: A bag contains 3 red and blue marbles. A marble is drawn without replacement. The probability that a second marble will be blue depends on what the first marble was.

Independent events: 2 ( or more ) events are independent if the outcome of the first event has no effect on the outcome of the second event.

Example: Given the same bag of marbles. A marble is drawn with replacement. The probability that the second marble is blue is unaffected by which marble was drawn first.

Alright well, that's all everybody, sorry there are no diagrams for the moment, I'm trying to fix my computer, it's hard enough trying to fully fix our connections. Anyways, it's that time again, the NEXT SCRIBE WILL BE PATRICK. GOOD LUCK ! =).