The regiоnаl mаnаger is cоmparing the perfоrmance of two sales agents from two different offices. Mary has earned commissions totaling $`x` while working in an office with mean commissions of $85000 and a standard deviation of $`y`. Robert has earned commissions totaling $`a` in an office with mean commissions of $61,000 and a standard deviation of $`b`. Calculate the z-scores for each sales agent to determine how they are each performing within their respective offices. For your answer below, enter the z-score for the better performing sales agent. Round your answer to two decimal places.