Discuss
what each aspect of this result means: F(1, 26) = 4.406, p
= 0.046.
4.Is
the change in the pain scores after 12 weeks of guided imagery statistically
significant for the intervention group? If yes, at what probability?
5.State
the null hypothesis for the effect of guided imagery on pain scores for the
subjects in the treatment group at 12 weeks. Should this null hypothesis be
accepted or rejected? Provide a rationale for your answer.
6.How
many means are being compared for the pain scores at 12 weeks?
7.What
did the researcher set the level of significance or alpha (a) at for this
study? When will study results be considered significant?
8.The
researchers do not report the standard deviations associated with the means.
Would you be interested in knowing the standard deviations? Provide a rationale
for your answer.
ANSWERS
TO STUDY QUESTIONS
1.A
repeated-measures ANOVA was conducted to examine differences between the
intervention group, receiving the treatment of GI and the control group over 12
weeks. The groups were examined for differences for the dependent variables of
pain and mobility over the 12-week time period. The repeated-measures ANOVA was
appropriate since the focus was on examining group differences over time. In
addition, the groups were independent due to random group assignment, and the
dependent variables (pain and mobility) were measured at least at the interval
level of measurement.
2.According
toFigure 1, the average pain scores for
the guided imagery intervention group and the control group were most similar
at baseline. This is what the researchers would hope for, since they had a
sample of 28 subjects who were randomly assigned to the treatment and control
groups to promote similarity of the groups at the start of the study. Thus if a
change occurred between the two groups during the study, it is assumed it is
due to the treatment and not because the groups were different at the start of
the study.
3.F(1,
26) = 4.406, p = 0.046, where F is the statistic for
ANOVA and the group df = 1 and the error df = 26. The F
ratio or value = 4.406, which is significant at p = 0.046
4.Yes,
F(1, 26) = 4.406, p = 0.046 is statistically
significant at p = 0.046. The level of significance for this study was
set at a = 0.05, and since p is
5.The
null hypothesis is: Women with OA receiving guided imagery have no greater
improvement in their pain scores than those in the control group at 12 weeks.
The study results indicated a significant improvement in the pain scores of
women with OA who received the treatment of guided imagery (F(1,
26) = 4.406, p = 0.046). Thus, the null hypothesis was
rejected.
6.Two
means are being compared at 12 weeks. The mean of the control group and the
mean of the guided imagery group for pain are being compared at 12 weeks.
7.The
researchers set the level of significance or alpha (a) = 0.05, which means that
any results with a p (probability) of = 0.05 will be considered
significant.
8.Answers
may vary, but it would be helpful to include the standard deviations with the
means since the standard deviations indicate the spread of the scores for the
two groups. The standard deviations for the treatment and control groups also
are needed to calculate the effect size or the effect of the treatment in a
study. The effect size is needed to conduct a power analysis to predict the
sample size needed for future studies. In addition, if the results from this
study were to be combined with the results from other studies, the means and
standard deviations for the treatment and control groups are needed to conduct
a meta-analysis to combine study results to determine current knowledge in an
area. In summary, it is helpful to report all means and standard deviations for
study variables whether the results are significant or nonsignificant, because
they are valuable to consider in conducting future research and meta-analyses.
Name:____________________________________________
Class: ____________________
Date:
_________________________________________________________________________________
? EXERCISE 36 Questions to be Graded
1.The
researchers found a significant difference between the two groups (control and
treatment) for change in mobility of the women with osteoarthritis (OA) over 12
weeks with the results of F(1, 22) = 9.619, p = 0.005.
Discuss each aspect of these results.
2.State
the null hypothesis for the Baird and Sands (2004) study that focuses on the
effect of the GI with PMR treatment on patients’ mobility level. Should the
null hypothesis be rejected for the difference between the two groups in change
in mobility scores over 12 weeks? Provide a rationale for your answer.
3.The
researchers stated that the participants in the intervention group reported a
reduction in mobility difficulty at week 12. Was this result statistically
significant, and if so at what probability?
4.If
the researchers had set the level of significance or a = 0.01, would the
results of p = 0.001 still be statistically significant? Provide a
rationale for your answer.
5.If
F(3, 60) = 4.13, p = 0.04, and a = 0.01, is the result
statistically significant? Provide a rationale for your answer. Would the null
hypothesis be accepted or rejected?
6.Can
ANOVA be used to test proposed relationships or predicted correlations between
variables in a single group? Provide a rationale for your answer.
7.If
a study had a result of F(2, 147) = 4.56, p = 0.003,
how many groups were in the study, and what was the sample size?
8.The
researchers state that the sample for their study was 28 women with a diagnosis
of OA, and that 18 were randomly assigned to the intervention group and 10 were
randomly assigned to the control group. Discuss the study strengths and/or
weaknesses in this statement.
9.In
your opinion, have the researchers established that guided imagery (GI) with
progressive muscle relaxation (PMR) reduces pain and decreases mobility
difficulties in women with OA?
10.The
researchers stated that this was a 12-week longitudinal, randomized clinical
trial pilot study with 28 women over 65 years of age with the diagnosis of OA.
What are some of the possible problems or limitations that might occur with
this type of study?
(Grove 267)
Grove, Susan K.. Statistics for Health Care
Research: A Practical Workbook. W.B. Saunders Company, 022007.
Attachments:
ANOVA-Excel-W….xlsx
