The salaries of professional baseball players are heavily skewed right with a mean of $3.2 million and a standard deviation of $2 million. The salaries of professional football players are also heavily skewed right with a mean of $1.9 million and a standard deviation of $1.5 million. A random sample of 40 baseball players' salaries and 35 ootball players' salaries is selected. The mean salary is determined for both samples. Let x bar b - x bar f represent the difference in the mean salaries for baseball and football players. Which of the following represents the standard deviation of the sampling distribution for x bar b - x bar f? .41 mil
.57 mil
2.5 mil
3.5 mil ​