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Unformatted text preview: n Sample Stdev 1 15 52 4.61 2 15 57 4.83 Test the alternative hypothesis that the mean lives
G. Baker, Department of Statistics
G.
are different.
University of South Carolina; Slide 10 How do we know if we can assume
How
equal variances?
equal
Confidence Interval on σ21/σ22
Hypothesis Test
Hypothesis
H0: σ21/σ22 = 1
Ha: σ21/σ22 = 1 G. Baker, Department of Statistics
G.
University of South Carolina; Slide 11 Test for Equal Variances
Confidence Interval Approach:
Confidence
– If CI does not contain 1 we have
If
sufficient evidence to conclude that the
variances are different. We can not
assume equal variances.
assume
– If the CI contains 1, we will continue to
If
assume that the variances are equal.
assume G. Baker, Department of Statistics
G.
University of South Carolina; Slide 12 Test for Equal Variances
Hypothesis Test Approach:
H0: σ21/σ22 = 1
Ha: σ21/σ22 = 1
If we reject H0, there is sufficient evidence to
conclude that the variances are different. We
can not assume equal variances.
If we fail to reject H0, we will continu...
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 Fall '13
 Wang
 Statistics

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