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 8 children are used for the experiment. First, a baseline of the number of times the children brush their teeth over a month's period is established. Next, the children are shown the dental film and again the number of teeth brushings are recorded for a month. The following data are recorded. Assume you are evaluating H 0 with the t test. The df for determining t crit equal _________.
A) 8
B) 16
C) 7
D) 14

Question

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 8 children are used for the experiment. First, a baseline of the number of times the children brush their teeth over a month's period is established. Next, the children are shown the dental film and again the number of teeth brushings are recorded for a month. The following data are recorded.  Assume you are evaluating H 0 with the t test. The df for determining t crit equal _________.
A) 8 
B) 16 
C) 7 
D) 14

Quizplus · Accepted Answer

The degrees of freedom (df) for a paired t-test is the number of pairs (n) minus 1, which in this case is 8-1=7. Therefore, the answer is C) 7.

A Health Educator Wants to Evaluate the Effect of a Dental