thanks for helpSolutionLet ud uafter ubefore Formulating t

thanks for help~

Solution

Let ud = u(after) - u(before).
              
Formulating the null and alternative hypotheses,              
              
Ho:   ud   >=   0  
Ha:   ud   <   0  
At level of significance =    0.05          
As we can see, this is a    left   tailed test.      
              
Calculating the standard deviation of the differences (third column):              
              
s =    19.0370566          
              
Thus, the standard error of the difference is sD = s/sqrt(n):              
              
sD =    4.915346877          
              
Calculating the mean of the differences (third column):              
              
XD =    -26.86666667          
              
As t = [XD - uD]/sD, where uD = the hypothesized difference =    0   , then      
              
t =    -5.465873994          
              
As df = n - 1 =    14          
              
Then the critical value of t is              
              
tcrit =    -   2.144786688      
              
As |t| > 2.1448, then we REJECT Ho.

Thus, there is significant evidence that the diet and excercise reduce cholesterol at 0.05 level. [CONCLUSION]