Show all your work for credit Solve the problemsl3 by answer
Solution
a)
Male and female high school students have equal mean ACT scores. [ANSWER]
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b)
Let
u1 = mean of male
 u2 = mean of female
Formulating the null and alternative hypotheses,              
               
 Ho:   u1 - u2   =   0  
 Ha:   u1 - u2   =/   0   [ANSWER]
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c)
At level of significance =    0.01          
 A
 s we can see, this is a    two   tailed test.      
 Calculating the means of each group,              
               
 X1 =    21.2          
 X2 =    20.9          
               
 Calculating the standard deviations of each group,              
               
 s1 =    4.9          
 s2 =    4.6          
               
 Thus, the standard error of their difference is, by using sD = sqrt(s1^2/n1 + s2^2/n2):              
               
 n1 = sample size of group 1 =    43          
 n2 = sample size of group 2 =    56          
Thus,
sD =    0.967589394          
               
 Thus, the z statistic will be              
               
 z = [X1 - X2 - uD]/sD =    0.310048872   [ANSWER]
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d)      
               
 where uD = hypothesized difference =    0          
               
 Now, the critical value for z is              
               
 zcrit =    +/-   2.576   [ANSWER]
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e)  
               
 As |z| < 2.576,   WE FAIL TO REJECT THE NULL HYPOTHESIS.          
               
 Thus, there is no significant evidence taht the mean scores of female and male high school students in ACT are different at 0.01 level. [CONCLUSION]


