In 1930,the Average Size of a Public Restroom Was 172 $\alpha$

Multiple Choice

In 1930,the average size of a public restroom was 172 square feet;by 1990,due to federal disability laws,the average size had increased to 471 square feet.Suppose that a design team believes that this standard has increased from the 1990 level.They randomly sample 23 public restrooms in a major Midwestern city and obtain a mean square footage of 498.78 with a standard deviation of 46.94.What is the critical value for $\alpha$ = .001 to test the hypotheses.

A) 3.792
B) 3.767
C) 3.505
D) 3.485
E) 3.09