QUESTION 12 A labor union claims that the mean income of its members is no more than $20,000 per year. The Employers' Association believes that this claim is too low and that the actual mean income is higher. A random sample of 64 union members yields a mean income of $20,278.50 with a standard deviation of $793.81. Calculate the standardized test statistic. O -0.35 O 0.35 O -2.81 O 2.81