In: Statistics and Probability
.Finance course grade information regarding male and female students of a large university is shown below (?"and ?!unknown) and assumed unequal).
| 
 Female  | 
 Male  | 
|
| 
 Sample Size  | 
 24  | 
 28  | 
| 
 Sample Mean Grade  | 
 29.8  | 
 27.3  | 
| 
 Sample Variance  | 
 6,554  | 
 3,276  | 
Not: You have to draw the table to see which area that you have to calculate
SOLUTION:
a)
Ho :   µ1 - µ2 =  
0          
Ha :   µ1-µ2 >   0  
       
          
       
Level of Significance ,    α =   
0.05          
          
       
Sample #1   ---->   1  
       
mean of sample 1,    x̅1=   29.80  
       
standard deviation of sample 1,   s1 =   
80.95677859          
size of sample 1,    n1=   24  
       
          
       
Sample #2   ---->   2  
       
mean of sample 2,    x̅2=   27.300  
       
standard deviation of sample 2,   s2 =   
57.24          
size of sample 2,    n2=   28  
       
          
       
difference in sample means = x̅1-x̅2 =   
29.800   -   27.3000   =  
2.5000
          
       
std error , SE =    √(s1²/n1+s2²/n2) =   
19.7505          
t-statistic = ((x̅1-x̅2)-µd)/SE = (   2.5000  
/   19.7505   ) =   0.1266
          
       
          
       
t-critical value , t* =       
1.6839   (excel function: =t.inv(α,df)  
   
Decision:   | t-stat | < | critical value |, so, Do
not Reject Ho          
   
p-value =        0.44995  
[excel function: =T.DIST.RT(t stat,df) ]  
   
Conclusion:     p-value>α , Do not reject null
hypothesis          
   
There is no enough evidence to support the claim
b)
Degree of freedom, DF=      
40          
t-critical value =    t α/2 =   
1.684   (excel formula =t.inv(α/2,df)  
   
          
       
          
       
          
       
std error , SE =    √(s1²/n1+s2²/n2) =   
19.751          
margin of error, E = t*SE =    1.684  
*   19.751   =   33.256946
          
       
difference of means = x̅1-x̅2 =    29.8000  
-   27.300   =   2.5000
confidence interval is       
           
Interval Lower Limit = (x̅1-x̅2) - E =   
2.5000   -   33.257   =  
-30.757
Interval Upper Limit = (x̅1-x̅2) + E =   
2.5000   -   33.257   =  
35.757
(OR) TRY THIS ANSWER
(a)

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(b)

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