1. A researcher hypothesizes that there will be a significant change in a student's fear of statistics following participation in an intervention designed to increase students' confidence in their ability to successfully complete a statistical course. The sample consists of nursing graduate students enrolled in a statistics course at a research university. Fear scores were recorded before and after the intervention. The possible range of scores for anxiety is 20 to 60. Higher scores indicate high levels of anxiety. The output table from her analysis is as follows:
|
Fear Score
|
n
|
Mean
|
Std Dev
|
t
|
df
|
p
|
|
Before Intervention (Time 1)
|
30
|
40.2
|
5.16
|
5.394
|
29
|
<0.0001
|
|
After Intervention (Time 2)
|
30
|
37.5
|
5.15
|
|
|
|
a. How many subjects are in the sample?
b. Based on the output, what conclusion can be made? Bold your answer.
I. There is a significant increase in fear of statistics scores from Time 1 to Time 2.
II. There is a significant decrease in fear of statistics scores from Time 1 to Time 2.
III. There is no significant difference in fear of statistics scores from Time 1 to Time 2.
IV. Unable to make a determination based on the information provided.
c. Is the research hypothesis supported based on these findings? Why or why not? Provide statistical evidence.
2. A researcher is interested in whether a nurse counseling intervention or use of the nicotine patch reduces the number of cigarettes smoked in one day. She presents the following data:
|
Group
|
N
|
Mean (SD) cigarettes smoked per day
|
F-Ratio and p-value
|
Multiple Comparisons
Nurse Counseling Nicotine Patch
|
|
Nurse
|
10
|
20 (13.2)
|
|
|
|
|
Counseling
|
|
|
F = 3.84
|
|
|
|
|
(p=.034)
|
|
Nicotine Patch
|
10
|
25 (10.3)
|
p = .579
|
|
|
No Treatment
|
10
|
33 (7.4)
|
p = .036
|
p = .257
|
a. What analysis method did the researcher use?
b. Which group smoked more cigarettes? What is the evidence?
c. Is there a statistical difference (at least one comparison) in the mean number of cigarettes smoked? What is the statistical evidence?
d. Which of the following statements is true? Bold your answer.
I. There is a significant difference between the nurse counseling group and the nicotine patch group.
II. There is a significant difference between the nicotine patch group and the no treatment group.
III. The no treatment group smoked significantly more cigarettes than the nurse counseling group.
IV. The no treatment group smoked significantly less cigarettes than both groups.