Understanding Statistics					 J.R. Rasmussen

					Class 7 Outline


I) Today's Class

	A) Go over assignment 3

	B) New York Times poll 

	C) Take home Quiz 1 and assignment 4


II) Summary of what we covered last class

	A) Binomial distribution
		1) Bernoulli trials
		2) tree of outcomes
		3) how to calculate on Excel
		4) example of birth of girls in a family of 3 children

	B) Introduction to random variables
		1) why we need:  "real world" vs "theoretical world"
		2) definition and examples
		3) mean :"mu"
		4) variance and standard deviation "sigma"

III) Go over assignment 3


IV) Break	


V) Statistical inference: New York times poll

	A) New York times poll: read  & hand out copy

	B) Draw the picture: real world/theoretical world

	C) How we view poll results as a binomial distribution
		1) The single trial. Pr(success)=Pr(favor), n=the size of our sample
		2) assume Pr(favor)=.40, we will poll a sample of size 100
		3) the expected number 

	D) Example: suppose we sample 100 people to see who they 
	are going to vote for
		1) Binomial set up:  Pr(favor)=.40
		2) expected number of successes
		3) look at 40 ± 10
		4) group exercise: have students do one, and report
		5) repeat until we have 160 observations
			a) I will keep track of frequency: the event E ( that 
			our result is between 30 and 50)

VI) Take home Quiz  

	A) Comments
		1) show work
		2) rules of quiz

	B) Hand out take home quiz:  due Monday 10/26/09

	C) Hand out assignment 4 due Wednesday 10/28/09