In: Statistics and Probability
| 
 Given independent random variables, X and Y, with means and standard deviations as shown, find the mean and standard deviation of each of the variables in parts a to d.  | 
|||
| a) X−11 b)0.7Y c)X+Y d)X−Y  | 
 Mean  | 
 SD  | 
|
|---|---|---|---|
| 
 X  | 
 90  | 
 13  | 
|
| 
 Y  | 
 20  | 
 5  | 
|
a) Find the mean and standard deviation for the random variable X-11.