3. Suppose you are a researcher studying treatments for
depression. Imagine three treatment groups (anti-depressant,
therapy,...
3. Suppose you are a researcher studying treatments for
depression. Imagine three treatment groups (anti-depressant,
therapy, and placebo) are being compared using Analysis of
Variance.
What effect would each of the following have on an F score (make
it smaller, make it larger, or cause no change)?
Explain why.
(Note: If you have trouble, look at the slides and consider the
formula F = variance between groups/variance within groups, and
consider what would influence that ratio).
a. A large within-group...
A researcher is interested in whether there is a significant
difference between the mean age of...
A researcher is interested in whether there is a significant
difference between the mean age of marriage across three racial
groups. Based on the data below, answer these questions.
Race
N
Mean
Black
118
21.57
White
882
24.59
Other
120
28.39
All Groups
1,120
24.68
1. Calculate the value of the between group sum of squares (SSB,
20 pts).
Race
Y bar for each group
Total mean
Group mean – Total mean
Square of the difference
The number of cases...
In an experiment designed to test the output levels of three
different treatments, the following results...
In an experiment designed to test the output levels of three
different treatments, the following results were obtained: SST =
320, SSTR = 130,
nT = 19.
Set up the ANOVA table. (Round your values for MSE and
F to two decimal places, and your p-value to four
decimal places.)
Source
of Variation
Sum
of Squares
Degrees
of Freedom
Mean
Square
F
p-value
Treatments
Error
Total
Test for any significant difference between the mean output
levels of the three treatments....
Three different treatments for hypertension (high blood
pressure) are being tested. A medical researcher takes volunteers...
Three different treatments for hypertension (high blood
pressure) are being tested. A medical researcher takes volunteers
and randomly assigns them into groups taking treatment A, B, and C.
The reduction in blood pressure is measured for each patient with
the following results:
In R: > dput(d$treatment)
c("A", "A", "A", "A", "A", "B", "B", "B", "B", "B", "B", "B",
"B", "B", "C", "C", "C", "C", "C", "C"
) > dput(d$reduction)
c(2.6, 4.5, 4.3, 4, 1.5, 4, -0.2, -2.4, 5, -1.8, 4.4,...
A researcher tests whether participation in community-sponsored
services (such as art classes, and field trips) increases...
A researcher tests whether participation in community-sponsored
services (such as art classes, and field trips) increases positive
attitude scores (as rated from 1 to 15). The researcher implemented
the community-sponsored services over a 6-month period and at the
end of the period, the researcher measured positive attitude scores
in the two groups. The researcher recruited a total of 14 senior
citizens (age 80 or older), and the group was divided into two
separate groups. The first group participated in the...
1.A researcher uses one-factor ANOVA to test the statistical
significance of differences among five treatments, with...
1.A researcher uses one-factor ANOVA to test the statistical
significance of differences among five treatments, with a sample of
n = 10 in each treatment group. The F-ratio for this analysis would
have what df values?
A. df = 5, 100
B. df = 4, 95
C. df = 4, 45
D. None of the above.
2. For a one-factor ANOVA comparing four treatment groups,
MSbetween = 32. What is the value of SSbetween?
A. 96
B. 80
C. 36...
A researcher wants to investigate a connection between systolic
blood pressure and body type to see...
A researcher wants to investigate a connection between systolic
blood pressure and body type to see if those with different body
types had different systolic blood pressures on average. Body type
is a categorical variable with levels 0 = Normal, 1 = Overweight,
and 2 = Obese.
Why should the researcher not use two-sample t-tests to see what
the differences are between the means of these three groups?