STAT 601 – Assignment #5 (Due Sunday, August 9th )
Review the following:
Lecture Handouts :
10 – Oneway ANOVA – Completely Randomized Block Designs
Narrated Powerpoint Lectures: under heading 11 – parts (a) - (c)
Non-narrated Powerpoint Lectures: under heading 11 – parts (a) – (c)
Please note: part (c) is covered in the Powerpoints for part (a) and (b), i.e. there is no separate
Powerpoint for (c).
RESEARCH PAPER QUESTIONS
1 - ANOVA and Multiple Comparisons in Published Research (13 pts.)
The paper “Gestational Diabetes Mellitus Upsets the Proportion of Fatty Acids in
Umbilical Arterial but Not Venous Plasma” by Alvino et al. is linked on D2L under the
heading “Gestational Diabetes”.
a) Table 1 presents the major results of the study. When comparing the levels of
different responses (palmitic acid, stearic acid, total SFAs, etc.) what three
populations are being compared using one-way ANOVA? (1 pt.)
b) What multiple comparison procedure did they use for making pairwise
comparisons and how did they denote which means were significantly different?
(2 pts.)
c) What statistical technique did they use to compare gestational diabetics (GDM) to
healthy women (Control)? (1 pt.)
d) For which responses and at which sites were significant differences between
gestational diabetics and healthy controls found? (2 pts.)
e) Consider the results for DHA (22:6 n-3) only which are presented below.
When comparing the means across cord blood location for controls or for
gestational diabetics one-way ANOVA was used. This is actually an incorrect
use of one-way ANOVA, why? (2 pts.)
f)
Another potential problem in this study is the experiment-wise error rate. For
example, consider the tests used to compare gestational diabetics vs. control on
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each response (palmitic acid, stearic acid, etc.) at each site (maternal vein, etc.),
how many tests like this were done total? How many Type I Errors can they
expect to see using an  = .05? How many significant differences were found?
(3 pts.)
g) Despite the problems mentioned in parts (e) and (f) did the authors effectively
summarize the results of these tests in terms of their research questions? Explain.
(2 pts.)
A note about F-notation for one-way ANOVA:
Fk-1,n-k = indicates the test statistic value. It measures the size of the between group
variation to the within group variation. The subscripts k - 1 and n - k denote the
numerator and denominator degrees of freedom for the F-test. k = the number of
treatments/populations being compared and n = the total sample size for the entire study.
This should be useful in answering some of the questions for the Guided Muscle
Relaxation study below.
2 – Guided Muscle Relaxation
Using the paper linked on D2L under the heading “Guided Muscle Relaxation” answer
the following questions:
a) 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.
b) 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 significance level?
c) If the researchers had set the level of significance at  = .01, would the results of
p = 0.001 still be statistically significant? Provide a rationale for your answer.
d) If F(3,60) = 4.13, p = .04, and , is the result statistically significant?
Provide a rationale for your answer. Would the null hypothesis be rejected or
not?
e) If a study had a result of F(2,147) = 4.56, p = .003, how many groups were in the
study, and what was the overall sample size?
f) 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.
g) In your opinion, have researchers established that guided imagery (GI) with
progressive muscle relaxation (PMR) reduces pain and decreases mobility
difficulties in women with OA?
h) 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 limitations that might occur with this type of
study?
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STATISTICAL ANALYSIS QUESTIONS
1 – Exercise Performance and Ipratropium Bromide Aerosol Dose
A study by Ikeda et al., (Thorax, 1996), was designed to determine the dose of
ipratropium bromide aerosol that improves exercise performance using progressive cycle
ergometry in patients with stable chronic obstructive pulmonary disease. The mean age
of the 20 male subjects was 69.2 years with a standard deviation of 4.6 years. Among the
data collected were the maximum ventilation (VEmax, L/min.) values at maximum
achieved exercise for difference ipratropium bromide dosage levels (  g). Each subject
in the study was tested at each of the dose levels.
Data File: VE max IBA
a) Analyze these data to determine if the mean maximum ventilation differs significantly
as a function of dose. Summarize your findings. (4 pts.)
b) Use Dunnett’s procedure to compare each dosage level with placebo. Which dosage
levels, if any, significantly differ from placebo? (3 pts.)
c) Assuming that the larger VE values are best, what dosage would you recommend?
Justify your choice. (3 pts.)
2 – Calcium Intake and Age for Women Between the Ages of 20-88 yrs.
Ilich-Ernst et al. in their paper “Critical Factors for Bone Health in Women across the
Age Span: How Important is Muscle Mass?” in Medscape Women’s Health eJournal
(2002) investigated dietary intake of calcium among a cross section of 113 healthy
women ages 20-88. The researchers formed four age groups as follows: Group A (20 –
45.9 years), Group B (46.0 – 55.9) years, Group C (56.0 – 65.9) years, and Group D (66+
years). Calcium from food intake was measured in mg/day and the results are contained
in the file Calcium Intake.JMP.
a) Is there evidence to suggest that calcium intake differs significantly across the age
groups? Conduct an appropriate test to answer this question. Be sure to check
assumptions required for your analysis. (4 pts.)
b) If there are significant differences, which age groups significantly differ in terms of
there mean calcium content? Also quantify and discuss any significant differences
you find. (4 pts.)
c) Write a short summary of your findings from parts (a) and (b). (2 pts.)
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3 – Length of Home Health Visits and Time of Day
The nursing supervisor in a local health department wished to study the influence of time
of day on length of home visits by the nursing staff. It was thought that individual
differences among the nurses might be large, so the nurse was used as a blocking factor.
The nursing supervisor collected the following data:
Length of Home Visit by Time of Day
Nurse
Early AM
Late AM
Early PM
Late PM
A
27
28
30
23
B
31
30
27
20
C
35
38
34
30
D
20
18
20
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Data File: Nurse Visit.
a) Conduct an appropriate test to determine if the mean length of visit is related to the
time of day. Summarize your findings. (4 pts.)
b) Conduct multiple comparisons to compare the mean lengths of stay between the
different times of the visits. Also examine CI’s for the differences in means. Summarize
your findings. (4 pts.)
4 - Tourette's Syndrome and Nicotine Gum
McConville et al. report the effects of chewing one piece of nicotine gum (containing 2
mg of nicotine) on tic frequency in patients whose Tourette's disorder was inadequately
controlled by haloperidol. In the study, the number of tics in a 30 minute period was
measured at baseline and then each patient was given a piece of nicotine gum. The
number of tics observed for the 30 minutes while they were chewing the gum was
recorded and then for the two consecutive half hour periods after they spit out the gum.
After eliminating patient effects, can we conclude that the mean number of tics differs
among the four conditions? These data are in the file Tourettes.JMP. (6 pts.)
The variables in the data file are:
 Patient – patient ID number
 Time Period –
1 - Base (baseline)
2 - Gum Chew (while chewing gum)
3 - 0 – 30 min (0 – 30 minutes after chewing gum)
4 - 30 – 60 min (30 – 60 minutes after chewing gum)
* Note: Each time period was 30 minutes in length

Tics/30 min – number of tics during the 30 minute period (response)
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a) Conduct an appropriate test to determine if the mean number of tics per 30 minute
period is related to the four conditions. Summarize your findings. (4 pts.)
b) Use an appropriate multiple comparison procedure to compare the mean number of
tics per 30 minutes across the different time periods. Also examine CI’s for the
differences in means. Summarize your findings. (4 pts.)
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