A health educator wants to evaluate the effect of a dental film on the frequency with which children brush their teeth. A random selection of 21 children are used for this experiment. First, a baseline of the number of times the children brush their teeth over a month's period is established. Next, the children were shown the dental film and the number of teeth brushing was recorded for a month. The mean difference was 1.5, with SSdof 280. With alpha set at .05 (two-tailed), answer questions 6-10. What type of test should be used? Correlated groups t test Sign Test Independent groups t test Campbell-Oswald t test