In a study of children with attention deficit hyperactivity disorder (ADHD), par
ID: 2957304 • Letter: I
Question
In a study of children with attention deficit hyperactivity disorder (ADHD), parents were asked to rate their child on a variety of items related to how well their child performs different tasks. One item was "has difficulty organizing work," rated on a five-point scale of 0 to 4 with 0 corresponding to " not at all" and 4 corresponding to "very much." THe mean rating for 282 boys with ADHD was reported as 2.22 with a standard deviation of 1.03.a.)Do you think that these data are Normally distributed? Explain why or why not.
b.)Is it appropriate to use the methods of this section to compute a 99% confidence interval? Explain why or why not.
c.) Find the 99% margin of error and the corresponding confidence interval. Write a sentence explaining the interval and the meaning of the 99% confidence level.
d.) The boys in this study were all evaluated at the Western Psychiatric Institute and Clinic at the Univerisyt of Pittsburgh. To what extent do you think the results could be generalized to boys with ADHD in other locations?
Explanation / Answer
a) We can't tell without looking at a graph of the data. b) The sample size is large, so Normality is not much of an issue. c) ME = 2.575*1.03/sqrt(282) = 0.16 We are 99% confident that the true mean is between 2.06 and 2.38. d) This is not a random sample of all boys. There might be something special about the boys at this clinic that makes them different from other boys.