3
Suppose we wanted to test the hypothesis that a control group of cancer patients (Group 1)
would report higher mean pain ratings than an experimental group receiving special massage
treatments (Group 2). Using the following information, the computed
t
statistic for
independent groups is
t=3.54
M
1 = 78.50
SD
1
2
= 42.10
n
1 =25
M
2 = 72.10
SD
2
2
= 39.70
n
2 =25
a)
What are the degrees of freedom?
:

1

Michelle Beccio Assignment 5 N6208
b)
Using α = .05 for a two-tailed test, is this
t
statistically significant?
c)
Write one or two sentences that could be used to report the results obtained for the
t
-test
in this question.
4
For question 3, assume that the pooled
SD
for the two groups is 7.05. Calculate the value of
d.
Would you say the effective size is large, medium, or small?
5
For each of the following
t
values, indicate whether the
t
is statistically significant for a two-
tailed test, at the specified alpha:
a.
t
= 2.40,
df
b.
t
= 2.40,
c.
t
= 5.52,
df
d.
t
= 2.02,
df
6
State the critical (tabled) value of
t
that would be used to reject the null hypothesis of
equality of population means, for an independent groups
t
-test under each of the following
conditions:
a.
H1: μ1 ≠ μ2;
n
1 = 20,
n
2 = 20; α = .05: