Understanding Statistics					 J.R. Rasmussen

					Class 5 Outline

I) Nuts & Bolts

	A) Quiz 1 will probably be next week.  Take home handed out on Wednesday 10/21 and due on Monday 10/26/09.


II) Homework

	A) Class turn in assignment 2
		1) Go over last problem on variability: example 4.3, pg. 143

	B) Go over homework


III) Summary of what we covered last class

	A) Introduction to probability
		1) little history
		2) basic ideas
			a) outcomes and  events
			b) frequency
		3) axioms
		4) examples

	B) introduction to statistical inference
		1) New York times poll
		2) Example of 4 tosses of a coin
			a) constructed tree of outcomes
			b) calculated the probability of exactly two heads
			c) we used Excel to see variability
			d) we used the binomial distribution with n=4
			e) students generated, 10, 100,1000, & 10000 examples
			f) used the frequency command & then compared 	
			the relative frequency of exactly 2 heads, with the theoretical value

IV) Our four coin example revisited: one more simulation of 10000

	A) Everyone do a simulation with 10000 outcomes

	B) Construct the frequency table & draw a histogram
		1) everyone get up and look at the histograms


V) Probability continued

	A) Random variables and probability distributions
		1) why we are looking at these concepts (inference)
		2) previous examples in new "language"
			a) heights of students in class
			b) toss two dice: sum on dice
			c) toss a coin, the number of heads
			d) length of time a light bulb burns
			e) amount of red blood cells in blood
		3) discrete and continuous
			a) count/measure
			b) class apply to examples above

Break	(Hand out assignment 3 (due 10/21/09) and reading handout)

VI) Probability continued

	B) A very useful example: binomial distribution
		1) General setup:  Bernoulli trials
		2) Tree view
		3) develop the probabilities
			a) recall our flip of 4 coins: tree of outcomes
			b) emergency calls example
				i) 4 calls
				ii) Pr(medical call)=85%
				iii) draw tree
				iv) construct probability distribution (picture)
			c) group exercise: birth of girls
				i) Pr(success)=Pr(girl)=.49
				ii) A family has three children
				iii) construct the probability distribution
				iv) find Pr(exactly two girls)
				v) find Pr(at least two girls)
				vi) find Pr(all boys)
		4) general formula, how to calculate:  Excel 


VII) Quiz 1 will probably be next week.  Take home handed out on Wednesday 10/21 and due on Monday 10/26/09.  
Assignment 3 will be due on Wednesday 10/21.