F IL E G iven a recent o u tb rea k o f illness caused by F. co li bacteria, th e m ayor in a large city is c oncern ed th a t s om e o f his restaurant inspectors are not consistent w ith their evaluation s o f a restaurant's cleanliness. In ord er to investigate this possibility, th e m ayor has five restaurant inspectors grade

(scale o f 0 to 100) th e cleanliness o f th re e restaurants. The results are show n in th e accom panying tab le and can also be found on th e text w ebsite, labeled R estau ran ts.

Inspector Restaurant 1 2 3 1 72 54 84 2 68 55 85 3 73 59 80 4 69 60 82 5 75 56 84

a. Use Excel to g en erate th e ANOVA table.

b. At th e 5 % significance level, can you conclude th a t average grades differ by restaurant?

c. If ave ra g e grades d iffer by restaurant, use Tukey's HSD test a t th e 5% significance level to d e te rm in e w hich averages differ.

d. A t th e 5 % significance level, can you conclude th a t the average grades differ by inspector? Does th e m ayor have cause for concern? P-69