Statistical Inference

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Statistical Inference
For a sample with a mean of 37.85 and S.D. of 9.5
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Confidence intervals

• 95 confidence interval the interval about the
  mean containing 95 of the observations
• Also stated there is a 95 chance that a sample
  mean will fall within that interval.

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Mean 47 s 7.2 (note this is the known s for
the Population
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Estimating s
If n is large (gt30) we can estimate s as s
(sample SD)
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In the real world, we rarely know the population
variance and we rarely are able to have an n gt
30. Therefore we routinely use the t statistic
instead of Z.
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Paired data
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