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              | Essential Question:
    Assuming an SRS and given equal 
              sized margins of error, is the sample size required to survey the 
              entire United States substantially larger than the one for 
              conducting the same survey in Greenville SC? |  Two-Sample Proportions 
        
          Calculate the desired 
          sample size for a given margin of error in a proportion (p. 696).
          Remember that p = 50% will give the max 
          sample size and hence most conservative estimate of the size needed. 
          Using the equation for margin of error, solve for n. 
          Relevance: 
                Survey results are a ubiquitous feature of newspaper and 
          magazine articles as well as political arguments.
                The above is the basic way that surveys are designed. 
                  Create a confidence 
            interval for comparing two sample proportions.          
          
            
              | Margin of Error 
                for Confidence Interval |  
              | 
                
                  | ME = | z* [  p̂1(1-p̂1) /n1 + p̂2(1-p̂2) /n2 ]0.5 |  |    State the Ho used for 
            comparing two sample proportions.  
            
              Ho: 
                p2 - p1 = 0  
                 
                or Ho: 
              p2 = p1 
        
          Calculate the pooled 
          portion of successes using both samples. 
          Pooled tests are generally run when testing 2 proportions because the 
          subjects are typically selected from a common pool but receive 
          different treatments--example: drug tests, heart attacks vs. fat in 
          diet, accident rate vs. drunkenness, etc. In all these examples, the 
          human subjects are typically drawn from the same population. 
            
            
                
                  | pc | =  | count of successes in both samples combined |  
                  | count of observations in both samples combined |  
                  |  |  |  |  
                  |  | = | X1 + X2 |  
                  | n1 
                  + n2 |  
        
          Perform a hypothesis test 
          for comparing two sample proportions. 
          Note: the TI-83 calculator automatically does a 
          pooled test when the 2-PropZTest option is selected          
           
            
              
                
                  | Test Statistic for  
                    Hypothesis Testing |  
                  | 
                    
                      | z = | (p̂1- p̂2) 
                        - 0 
 |  
                      | [  p̂c(1-p̂c) /n1 + p̂c(1-p̂c) /n2 ]0.5 |  |              
      Homefun 
          
          (formative/summative assessment): 
          Read 10.1, Exercises 1, 3, 7, 9, 13
          pp. 621 to 623
       
           
            
              | Essential Question: How What is the standard error (standard deviation of the sampling distribution) for the difference between 2 means when population std deviations are known? |  
           
            State that the sampling distribution mean for the difference between samples drawn from two different populations is the same as the difference between the the two population means.
              
                
                  In other words,  the mean of the sampling distribution for ( x-bar1 - x-bar2 ) is ( μ1 - μ2 )Given the standard deviations of 2 different populations, calculate the standard error for the sampling distribution of the difference between the two means. 
              
                
                  
                    
                      | SE = | ( σ12/ n1 + σ22/ n2 )  0.5 |  Homefun   (formative/summative assessment):
            Read 10.2, Exercises
          35, 37 p. 652
                     
           
           
            
              | Essential Question: How can you determine if 2 
                populations differ if at the start you have no information? |   Two-Sample t-Test
           
            
              State the assumptions made 
                for two-sample tests. (p. 650)
               
                SRS used for generating the 
                  sample  independent - matched pairs violate independence  normally 
                  distributed  population
              Create confidence intervals 
                and hypothesis test using two sample t procedures assuming that the 
                sigmas of the two populations are unequal. This is the most 
                conservative assumption.              
             
            
              Ho: μ1 - μ2 = 0  but can also 
                be written, Ho:  μ1 = μ2  
                
               
                
                  | Test Statistic for  
                    Hypothesis Testing | Margin of Error 
                    for Confidence Interval |  
                  | 
                    
                      | t = | (xbar1 - xbar2) 
                        - 0 
 |  
                      | (s12/n1 + s22/n2)0.5 |  | 
                    
                      | ME = | t* (s12/n1 + s22/n2)  0.5 |  |  
            
              Create confidence intervals 
                and hypothesis test using two sample t procedures and the most 
                conservative method of determining df.               
             
            
              df = (the lower of n1 -1 
                or n2 - 1)              
             
            
              Be aware of the more 
                accurate way to calculate df as is done by the TI-83 calculator. This method can return a df that includes a decimal fraction. For example: df = 12.37              
            
              Perform two sample 
                hypothesis t-procedures on the TI-83.               
            
              State the key assumption 
                required for using the pooled two-sample t-procedures. This is the method is an option in the TI-83 
                  calculator.              
             
            
                The sigmas of the two populations are 
                the same
                               
             Homefun 
            (formative/summative assessment): Exercises
          39, 
          43, 47, 45, 67, 69, 71, 75 pp. 652 to 660
           Chapter 10 AP Statistics Practice Test multiple choice and free response pp. 664 to 666                 
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