The known standard deviation in salary for all mid-level professionals in the financial industry is \($11,000\). Company A and Company B are in the financial industry. Suppose samples are taken of mid-level professionals from Company A and from Company B. The sample mean salary for mid-level professionals in Company A is \($80,000\). The sample mean salary for mid-level professionals in Company B is \($96,000\). Company A and Company B management want to know if their midlevel professionals are paid differently, on average.

Indicate if the hypothesis test is for

a. independent group means, population standard deviations, and/or variances known

b. independent group means, population standard deviations, and/or variances unknown

c. matched or paired samples

d. single mean

e. two proportions

f. single proportion