A professor gives his class a final examination that, he knows from years of experience, yields a population mean of 88. His present class of 22...

A professor gives his class a final examination that, he knows from years of experience, yields a population mean of 88. His present class of 22 obtains a mean of 92 and a standard deviation of 4. Is he correct in assuming that the performance of the most recent class is significantly better than that of other classes? Use a one-tailed test here--since the professor assumes that the class will score higher. Significance level: alpha = .05. Calculate the statistic.