10. if an experiment is conducted with 5 conditions and 6
10. If an experiment is conducted with 5 conditions and 6 subjects in each condition, what are dfn and dfe?
17. The following data are from a hypothetical study on the effects of age and time on scrores on a test of reading comprehension. Compute the analysis of variance summary table.
ADHD Treatment (AT) case study
28. (AT) The dataset ADHD Treatment has four scores per subject.
a. Is the design between-subjects or within-subjects?
b. Create an ANOVA summary table.
The ADHD Case Study for question 28.
Treatment Effects of a Drug on Cognitive Functioning in Children with Mental Retardation and ADHD
Research conducted by: Pearson et al. (2003, see reference below)
Case study prepared by: David Lane and Emily Zitek
Overview
This study investigated the cognitive effects of stimulant medication in children with mental retardation and Attention-Deficit/Hyperactivity Disorder. This case study shows the data for the Delay of Gratification (DOG) task. Children were given various dosages of a drug, methylphenidate (MPH) and then completed this task as part of a larger battery of tests. The order of doses was counterbalanced so that each dose appeared equally often in each position. For example, six children received the lowest dose first, six received it second, etc. The children were on each dose one week before testing.
This task, adapted from the preschool delay task of the Gordon Diagnostic System (Gordon, 1983), measures the ability to suppress or delay impulsive behavioral responses. Children were told that a star would appear on the computer screen if they waited “long enough” to press a response key. If a child responded sooner in less than four seconds after their previous response, they did not earn a star, and the 4-second counter restarted. The DOG differentiates children with and without ADHD of normal intelligence (e.g., Mayes et al., 2001), and is sensitive to MPH treatment in these children (Hall &Kataria, 1992).
D0 D15 D30 D60
57 48 64 62
27 42 48 49
32 39 34 30
31 23 25 34
34 36 42 38
38 34 40 36
71 61 59 77
33 36 42 51
34 41 36 45
53 57 67 42
36 32 29 43
42 48 50 57
26 48 44 36
52 39 57 58
36 36 36 35
55 48 57 60
36 35 30 33
42 39 36 49
36 32 41 33
54 48 65 59
34 35 35 35
29 28 40 37
33 27 43 45
33 40 44 29
Design Issues
This is a repeated-measures design because each participant performed the task after each dosage.
Descriptions of Variables
|
Variable |
Description |
|
d0 |
Number of correct responses after taking a placebo |
|
d15 |
Number of correct responses after taking .15 mg/kg of the drug |
|
d30 |
Number of correct responses after taking .30 mg/kg of the drug |
|
d60 |
Number of correct responses after taking .60 mg/kg of the drug |
The link to the ADHD case study http://onlinestatbook.com/2/case_studies/adhd.html
69. A researcher wants to know if the mean times (in minutes) that people watch their favorite news station are the same. Suppose that Table 13.24 shows the results of a study.
Assume that all distributions are normal, the four population standard deviations are approximately the same, and the data were collected independently and randomly. Use a level of significance of 0.05.
