Assignment 12

Probability is a pretty easy concept that I do not want to spend too much time on in class, since it will make up very little of your exam AND most all of you have seen these concepts before.

Probability of an event can be between 0 and 1. This makes sense. The lowest a probability can be is something has 0% chance of happening. And nothing can have more than 100% of something happening.

If there is a distribution of probabilities, they should all add up to 1. Again, this makes sense. As an example, let's say we got the probability of college students at BYU having 0, 1, 2, 3, 4+ roommates. The distribution may look like:

0 | 1 | 2 | 3 | 4+ |
.05 .10 .10 .30 .45

As you notice, .05+.10+.10+.30+.45 = 1. This is because at BYU, you HAVE to have one of those options (you cannot have less than 0 roommates, and I have covered everything in "4+"). So it has to encompass 100%.

Questions 1-4
Pretty straight forward. Choose the proportion that makes the most sense.

Questions 5-7
The key to these questions is writing out the right possibilities. Make sure you get every possible combination. I'll give you the first FOUR as a hint...but you need to come up with the rest.

GGG
GGB
GBG
BGG

The hard part for most people about these questions is the whole "x=2". X stands for the number of girls a couple has. So when x=2, it means how many arrangements are there only two girls: no more, no less.

For question 7, remember all you know about probability. What are all the values that "X" (number of girls in the combination) that can be possible? Look at your arrangements. Make sure they add up to 1!

The rest of the assignment is about parameter versus statistics, experimental design and association versus causation. We have gone over the last two extensively in class, and they are good reviews for the exam! Statistic versus parameter we will discuss in class.

Good Luck!