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ANOVA
Hypothesis Testing Steps
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View Full Document Calculating Variance: Review
df
SS
=
2
s
( 29
1
s
2
2


=
∑
N
M
x
Sum of
Squares
degrees of
freedom
Example
•
Retail store locations
•
Unequal sample sizes
DV = customer satisfaction
(higher = more satisfaction)
IV = region
Null:
There is no difference in
customer satisfaction between
regions.
Research:
There is a difference.
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View Full Document West
Midwest East
South
14
20
15
20
16
25
15
20
25
19
24
19
27
20
22
M =
18.33
M =
22.6
M =
18.5
M =
19.67
Little Between, Much Within: Are
the groups different?
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View Full Document Step 1: Sample 1
What is the sample size of sample 1?
n
1
= 3
Calculate the degrees of freedom for sample 1.
df
1
= 31 = 2
Calculate the sum of squares for sample 1.
∑(XM
1
)
2
= 18.75 + 5.43 + 44.49 = 68.67
Calculate the variance for sample 1.
s
2
1
= ∑(XM
1
)
2
/df
1
= 68.67/2 = 34.34
Calculate the standard deviation for sample 1.
s
1
= square root of s
2
1
= 5.86
X
(XM)
(XM)
2
14
4.33
18.7489
16
2.33
5.4289
25
6.67
44.4889
M =
18.33
West (sample 1
)
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View Full Document
What is the sample size of sample 2?
n
2
= 5
Calculate the degrees of freedom for sample 2.
df
2
= 51 = 4
Calculate the sum of squares for sample 2.
∑(XM
2
)
2
= 6.76 + 5.76 + 12.96 + 19.36 + 0.36 =
45.2
Calculate the variance for sample 2.
s
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This note was uploaded on 05/26/2011 for the course PSCH 343 taught by Professor Victoriaharmon during the Spring '11 term at Ill. Chicago.
 Spring '11
 VictoriaHarmon

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