c. Do the data provide sufficient evidence to indicate a
difference among the population means?
Test using α = .10.
d. Find the approximate observed significance level for the
test in part
c
, and interpret it.
e. Suppose that Do the data provide sufficient evidence to
indicate a difference between µ1 and µ2? Assume that there
are six observations for each treatment.
Test using α = .10
f. Refer to part b.
Find a 90%
confidence interval for (µ1 – µ2).
g. Refer to part b.
Find a 90%
confidence interval for µ1.

4. The data in the table below resulted from an experiment
that utilized a completely randomized design.
Treatment 1
Treatment 2
Treatment 3

3.8
5.4
1.3
1.2
2.0
0.7

4.1
4.8
2.2
5.5
3.8

2.3
a. Use SPSS to generate an ANOVA analysis and attach a
copy of the output:
b. Test the null hypothesis that µ1 = µ2 = µ3, where µ
i
represents the true mean for treatment I, against the
alternative that at least two of the means differ. Use
α = .01.
5. An accounting firm that specializes in auditing the
financial records of large corporations is interested in
evaluating the appropriateness of the fees it charges for its

services.
As part of its evaluation, it wants to compare the
costs it incurs in auditing corporations of different sizes.
The accounting firm decided to measure the size of its client
corporations in terms of their annual sales.
Its population of
client corporations was divided into three subpopulations,
with
A: Those with sales over $250 million
B:
Those with sales between $100 million and $250 million
C:
Those with sales under $100 million
The firm chose random samples of 10 corporations from each
of the subpopulations and determined the costs (in thousands
of dollars) as shown in the table below;
A

B
C
250
100
80
150

150
125
275
75
20
100

200
186
475
55
52
600

80
92
150
110
88
800

160
141
325
132
76
230

233
200
a. Construct an ANOVA analysis. Conduct a test to determine
whether the three classes of firms have different mean costs
incurred in audits.
Use α = .05.
b. What is the observed significance level for the test in part
b? Interpret it.

#### You've reached the end of your free preview.

Want to read all 30 pages?

- Fall '19
- Statistics, Statistical hypothesis testing