Understanding Statistics					 J.R. Rasmussen

					Class 12 Outline

I) Today's Class

	A) Go over quiz 2
	B) Game plan for rest of the term 
	C) New application of Rules 1-4: Hypothesis testing


II) Go over quiz 2


III) Game plan for remainder of term

	A) new applications of Rules 1-4
		1) Terminology of each application

	B) paired data
		1) descriptive statistics
		2) applications

	

IV) A new application on Rules 1-4:  Hypothesis testing

	A) Introduction:  Tennis Ball example
		1) Machine set to manufacture tennis balls with "mu" =3
		2) Noticing tennis balls are varying in size
		3) recalibrating the machine is expensive
		4) want to be sure that recalibrating is necessary and that 	
		we are not just observing random fluctuations
		5) want to test "mu" =3  (called the null hypothesis)
		6) will use a random sample to help us decide
		7) the alternative hypothesis

	B) Another example
		1) K-mart claims the avg. life a light bulb is 1000 hours
		2) customer would be mislead if "mu" < 1000
		3) Set up null hypothesis and alternative hypothesis


V) Break	


Outline 12  continued

VI) Hypothesis testing  (continued)

	C) Errors
		1) Jury example: make table of what can happen
		2) Type I error
		3) Type II error

	D) Level of significance
		1) "alpha" =level of significance=Pr(Type I error)

	E) Construction of a test: tennis ball example
		1) sample of 36 yields an average of 3.1 and s=.32
		1) test statistic
		2) level of test
		3) rejection region and critical value: picture
		4) do the test

	F) Example 10.14 pages 486-488
		1) P-values 

	G) Group exercises
		1) problem 10.24 a, c, e  page 479
		2) problem 10.25 b,c  page 480
		3) problem 10.49  page 491


VII) Hand out assignment 6, due on Monday August 8, 2011

	A) Work session on assignment 6