Happiness comes not from material wealth but less desire.
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Transcript of Happiness comes not from material wealth but less desire.
Happiness comes not from material wealth but less desire.
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Inferences Comparing Two Population Means
Paired samplesIndependent samples
Estimation Tests- z test and t test
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Paired Samples
If the same set of sources are used to obtain data representing two populations, the two samples are called paired. The data might be paired:– As a result of the data from certain “before” and
“after” studies– From matching two subjects to form “matched
pairs”
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Tests for Paired Samples
Calculate the pair differences Proceed as in one sample case
Example: Figure 11.1
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Independent Samples
The two samples are unrelated
Example: Chapter 11, problem 15 (heart.mpj)
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Estimation for
Point estimator Confidence interval
1. Normal populations with known , or two large samples (n1,n2>30): Z interval
2. Normal populations with unknown t interval : pooled t interval : approximate t interval
3. At least one nonnormal population and at least one small sample: out of our scope
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Two Populations
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Tests for d0
1. Normal populations with known , or two large samples (n1,n2>30): Z test
2. Normal populations with unknown t test : pooled t test : approximate t test
3. At least one nonnormal population and at least one small sample: out of our scope
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Two Populations
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Minitab: stat>>basic statistics>>2 sample t …
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Results for: HEART.MTW Two-Sample T-Test and CI: pdi, trtment
Two-sample T for pdi
trtment N Mean StDev SE Mean 0 73 91.9 16.5 1.9 1 70 97.8 14.7 1.8
Difference = mu (0) - mu (1) Estimate for difference: -5.85 95% CI for difference: (-11.02, -0.68) T-Test of difference = 0 (vs not =): T-Value = -2.24 P-Value = 0.027 DF = 141 Both use Pooled StDev = 15.6318
Two-Sample T-Test and CI: pdi, trtment
Two-sample T for pdi
trtment N Mean StDev SE Mean 0 73 91.9 16.5 1.9 1 70 97.8 14.7 1.8
Difference = mu (0) - mu (1) Estimate for difference: -5.85 95% CI for difference: (-11.01, -0.70) T-Test of difference = 0 (vs not =): T-Value = -2.24 P-Value = 0.026 DF = 140
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