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					|  |  |  |  | ** t-test | 
			
		
	
		
			
				
					|  |  |  |  | ** t-test for means                                                  :slide: | 
			
		
	
		
			
				
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					|  |  |  |  | ***  Testing if the mean is different from a specified value (say zero) :slide: | 
			
		
	
		
			
				
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					|  |  |  |  | #+name: ttest1 | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src R :results output list org | 
			
		
	
		
			
				
					|  |  |  |  |   readRDS("plfsdata/plfsacjdata.rds")->worker | 
			
		
	
		
			
				
					|  |  |  |  |   worker$standardwage->worker$wage | 
			
		
	
		
			
				
					|  |  |  |  |   worker->t9 | 
			
		
	
		
			
				
					|  |  |  |  |   t.test(t9$wage) | 
			
		
	
		
			
				
					|  |  |  |  | #+end_src | 
			
		
	
		
			
				
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					|  |  |  |  | #+RESULTS: ttest1 | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src org | 
			
		
	
	
		
			
				
					|  |  |  | @ -296,40 +306,38 @@ | 
			
		
	
		
			
				
					|  |  |  |  | - 291.031 | 
			
		
	
		
			
				
					|  |  |  |  | #+end_src | 
			
		
	
		
			
				
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					|  |  |  |  | #+name: ttest1 | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src R :results output list org | 
			
		
	
		
			
				
					|  |  |  |  |   readRDS("plfsdata/plfsacjdata.rds")->worker | 
			
		
	
		
			
				
					|  |  |  |  |   worker$standardwage->worker$wage | 
			
		
	
		
			
				
					|  |  |  |  |   worker->t9 | 
			
		
	
		
			
				
					|  |  |  |  |   t.test(t9$wage) | 
			
		
	
		
			
				
					|  |  |  |  | #+end_src | 
			
		
	
		
			
				
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					|  |  |  |  | *** Testing equality of means                                       :slide: | 
			
		
	
		
			
				
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					|  |  |  |  | + Here we test if the mean wages of men and women are equal. | 
			
		
	
		
			
				
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					|  |  |  |  | #+name: ttest2 | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src R :results output | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src R :results output list org | 
			
		
	
		
			
				
					|  |  |  |  |   subset(worker,sex!=3)->t9 | 
			
		
	
		
			
				
					|  |  |  |  |   factor(t9$sex)->t9$sex | 
			
		
	
		
			
				
					|  |  |  |  |   t.test(wage~sex,data=t9) | 
			
		
	
		
			
				
					|  |  |  |  | #+end_src | 
			
		
	
		
			
				
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					|  |  |  |  | #+RESULTS: ttest2 | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_example | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src org | 
			
		
	
		
			
				
					|  |  |  |  | - Welch Two Sample t-test | 
			
		
	
		
			
				
					|  |  |  |  | - data:  wage by sex | 
			
		
	
		
			
				
					|  |  |  |  | - t = 79.02, df = 13483, p-value < 0.00000000000000022 | 
			
		
	
		
			
				
					|  |  |  |  | - alternative hypothesis: true difference in means is not equal to 0 | 
			
		
	
		
			
				
					|  |  |  |  | - 95 percent confidence interval: | 
			
		
	
		
			
				
					|  |  |  |  | - 104.6563 109.9805 | 
			
		
	
		
			
				
					|  |  |  |  | - sample estimates: | 
			
		
	
		
			
				
					|  |  |  |  | - mean in group 1 mean in group 2  | 
			
		
	
		
			
				
					|  |  |  |  | - 310.8974        203.5790 | 
			
		
	
		
			
				
					|  |  |  |  | #+end_src | 
			
		
	
		
			
				
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					|  |  |  |  | 	Welch Two Sample t-test | 
			
		
	
		
			
				
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					|  |  |  |  | data:  wage by sex | 
			
		
	
		
			
				
					|  |  |  |  | t = 79.02, df = 13483, p-value < 0.00000000000000022 | 
			
		
	
		
			
				
					|  |  |  |  | alternative hypothesis: true difference in means is not equal to 0 | 
			
		
	
		
			
				
					|  |  |  |  | 95 percent confidence interval: | 
			
		
	
		
			
				
					|  |  |  |  |  104.6563 109.9805 | 
			
		
	
		
			
				
					|  |  |  |  | sample estimates: | 
			
		
	
		
			
				
					|  |  |  |  | mean in group 1 mean in group 2  | 
			
		
	
		
			
				
					|  |  |  |  |        310.8974        203.5790 | 
			
		
	
		
			
				
					|  |  |  |  | #+end_example | 
			
		
	
		
			
				
					|  |  |  |  | ** Testing for equality of proportions                               :slide: | 
			
		
	
		
			
				
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					|  |  |  |  | + Here we test if proportion of person who have passed high school is different for men and women | 
			
		
	
		
			
				
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					|  |  |  |  | #+name: proptest1 | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src R :results output | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src R :results output list org | 
			
		
	
		
			
				
					|  |  |  |  |   subset(worker,sex!=3)->t9 | 
			
		
	
		
			
				
					|  |  |  |  |   as.numeric(t9$gen_edu_level)->t9$gen_edu_level | 
			
		
	
		
			
				
					|  |  |  |  |   factor(t9$sex)->t9$sex | 
			
		
	
	
		
			
				
					|  |  |  | @ -338,18 +346,18 @@ mean in group 1 mean in group 2 | 
			
		
	
		
			
				
					|  |  |  |  |   prop.test(a$schooled,b$all) | 
			
		
	
		
			
				
					|  |  |  |  | #+end_src | 
			
		
	
		
			
				
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					|  |  |  |  | #+CAPTION: Results of test for equality of proportions of men and women who have passed secondary school | 
			
		
	
		
			
				
					|  |  |  |  | #+RESULTS: proptest1 | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_example | 
			
		
	
		
			
				
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					|  |  |  |  | 	2-sample test for equality of proportions with continuity correction | 
			
		
	
		
			
				
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					|  |  |  |  | data:  a$schooled out of b$all | 
			
		
	
		
			
				
					|  |  |  |  | X-squared = 847.73, df = 1, p-value < 0.00000000000000022 | 
			
		
	
		
			
				
					|  |  |  |  | alternative hypothesis: two.sided | 
			
		
	
		
			
				
					|  |  |  |  | 95 percent confidence interval: | 
			
		
	
		
			
				
					|  |  |  |  |  -0.1694726 -0.1525728 | 
			
		
	
		
			
				
					|  |  |  |  | sample estimates: | 
			
		
	
		
			
				
					|  |  |  |  |     prop 1     prop 2  | 
			
		
	
		
			
				
					|  |  |  |  | 0.09245986 0.25348253 | 
			
		
	
		
			
				
					|  |  |  |  | #+end_example | 
			
		
	
		
			
				
					|  |  |  |  | #+begin_src org | 
			
		
	
		
			
				
					|  |  |  |  | - 2-sample test for equality of proportions with continuity correction | 
			
		
	
		
			
				
					|  |  |  |  | - data:  a$schooled out of b$all | 
			
		
	
		
			
				
					|  |  |  |  | - X-squared = 847.73, df = 1, p-value < 0.00000000000000022 | 
			
		
	
		
			
				
					|  |  |  |  | - alternative hypothesis: two.sided | 
			
		
	
		
			
				
					|  |  |  |  | - 95 percent confidence interval: | 
			
		
	
		
			
				
					|  |  |  |  | - -0.1694726 -0.1525728 | 
			
		
	
		
			
				
					|  |  |  |  | - sample estimates: | 
			
		
	
		
			
				
					|  |  |  |  | - prop 1     prop 2  | 
			
		
	
		
			
				
					|  |  |  |  | - 0.09245986 0.25348253 | 
			
		
	
		
			
				
					|  |  |  |  | #+end_src | 
			
		
	
		
			
				
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