orry, no chi-square We would prefer to learn from teachers who know their subject. Perhaps even preschool children are affected by how knowledgeable they think teachers are. Assign 48 three- and four-year-olds at random to be taught the name of a new toy by either an adult who claims to know about the toy or an adult who claims not to know about it. Then ask the children to pick out a picture of the new toy in a set of pictures of other toys and say its name. The response variable is the count of right answers in four tries.

Here are the data:31 Correct Answers 0 1 2 3 4 Knowledgeable teacher 5 1 6 3 9 Ignorant teacher 20 0 3 0 1 The researchers report that children taught by the teacher who claimed to be knowledgeable did significantly better (c2 = 20.24, P < 0.05). Explain why this result isn’t valid.