4. Salary information regarding male and female employees of a large company is shown below. Male Female Sample Size 64 36 Sample Mean Salary (in $1000) 44 41 Population Variance ( ) 128 72 If you are interested in testing whether or not the population average salary of males is significantly greater than that of females, at = .05, the conclusion is that the population a. average salary of males is significantly greater than females. b. average salary of males is significantly lower than females. c. salaries of males and females are equal. d. average salary of males is greater than females cannot be proved