In: Statistics and Probability
The income of males in each state of the United States, including the District of Columbia and Puerto Rico, are given in table #9.3.3, and the income of females is given in table #9.3.4 ("Median income of," 2013). Is there enough evidence to show that the mean income of males is more than of females? Test at the 1% level.
Table #9.3.3: Data of Income for Males
| 
 $42,951  | 
 $52,379  | 
 $42,544  | 
 $37,488  | 
 $49,281  | 
 $50,987  | 
 $60,705  | 
| 
 $50,411  | 
 $66,760  | 
 $40,951  | 
 $43,902  | 
 $45,494  | 
 $41,528  | 
 $50,746  | 
| 
 $45,183  | 
 $43,624  | 
 $43,993  | 
 $41,612  | 
 $46,313  | 
 $43,944  | 
 $56,708  | 
| 
 $60,264  | 
 $50,053  | 
 $50,580  | 
 $40,202  | 
 $43,146  | 
 $41,635  | 
 $42,182  | 
| 
 $41,803  | 
 $53,033  | 
 $60,568  | 
 $41,037  | 
 $50,388  | 
 $41,950  | 
 $44,660  | 
| 
 $46,176  | 
 $41,420  | 
 $45,976  | 
 $47,956  | 
 $22,529  | 
 $48,842  | 
 $41,464  | 
| 
 $40,285  | 
 $41,309  | 
 $43,160  | 
 $47,573  | 
 $44,057  | 
 $52,805  | 
 $53,046  | 
| 
 $42,125  | 
 $46,214  | 
 $51,630  | 
Table #9.3.4: Data of Income for Females
| 
 $31,862  | 
 $40,550  | 
 $36,048  | 
 $30,752  | 
 $41,817  | 
 $40,236  | 
 $47,476  | 
 $40,500  | 
| 
 $60,332  | 
 $33,823  | 
 $35,438  | 
 $37,242  | 
 $31,238  | 
 $39,150  | 
 $34,023  | 
 $33,745  | 
| 
 $33,269  | 
 $32,684  | 
 $31,844  | 
 $34,599  | 
 $48,748  | 
 $46,185  | 
 $36,931  | 
 $40,416  | 
| 
 $29,548  | 
 $33,865  | 
 $31,067  | 
 $33,424  | 
 $35,484  | 
 $41,021  | 
 $47,155  | 
 $32,316  | 
| 
 $42,113  | 
 $33,459  | 
 $32,462  | 
 $35,746  | 
 $31,274  | 
 $36,027  | 
 $37,089  | 
 $22,117  | 
| 
 $41,412  | 
 $31,330  | 
 $31,329  | 
 $33,184  | 
 $35,301  | 
 $32,843  | 
 $38,177  | 
 $40,969  | 
| 
 $40,993  | 
 $29,688  | 
 $35,890  | 
 $34,381  | 
Ho :   µ1 - µ2 =   0  
       
Ha :   µ1-µ2 >   0  
       
          
       
Level of Significance ,    α =   
0.01          
          
       
Sample #1   ----> male   
mean of sample 1,    x̅1=  
46453.31          
standard deviation of sample 1,   s1 =   
7030.712514          
size of sample 1,    n1=   52  
       
          
       
Sample #2   ---->   female
  
mean of sample 2,    x̅2=  
36511.000          
standard deviation of sample 2,   s2 =   
6138.12          
size of sample 2,    n2=   52  
       
          
       
difference in sample means = x̅1-x̅2 =   
46453.308   -   36511.0000  
=   9942.3077
          
       
std error , SE =    √(s1²/n1+s2²/n2) =   
1294.2733          
t-statistic = ((x̅1-x̅2)-µd)/SE = (  
9942.3077   /   1294.2733   )
=   7.6818
          
       
Degree of freedom, =   100      
   
          
       
p-value =       
0.0000   [excel function: =T.DIST.RT(t stat,df)
]  
  
Conclusion:     p-value<α , Reject null
hypothesis      
   
  
there is enough evidence that  mean income of males is
more than of females