A m a n a g e m e n t consultan t w an ts to d e te rm in e w h e th e r th e age an d g e n d er o f a restaurant's w a it staff influence th e size o f th e tip th e c u s to m e r leaves. T h re e a g e brackets

(factor A in colum ns: youn g, m id d le -a g e , older) and g e n d er

(factor B in rows: m ale, fe m a le ) are used to construct a ran d o m block e xp erim e n t. For each co m b in atio n , th e p e rc e n ta g e o f th e to ta l bill le ft as a tip fo r 10 w a it s ta ff is e x a m in e d . T h e fo llo w in g A N O V A ta b le w ith α = 0.01 is produced.

ANOVA Source of Variation SS df MS F p-value F crit Sample 0.04278 1 0.04278 16.5951 0.00015 7.129 Columns 0.01793 2 0.00897 3.47884 0.03792 5.021 Interaction 0.00561 2 0.00281 1.08872 0.34392 5.021 Within 0.1392 54 0.00258 Total 0.20552 59

a. Can you co n c lu d e th a t th e re is in tera ctio n b e tw e e n a g e and g en d er at th e 1% significance level?

b. Are you able to conduct tests based on th e m ain effects?

If yes, c o n d u c t th e s e tests a t t h e 1 % significance level.

If no, exp lain .