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Unformatted text preview: Confidence Intervals Parameter Estimation We use statistics to estimate parameters, e.g., effectiveness of pilot training, psychotherapy. μ → X σ → SD Standard Error of the Mean This means that the standard error gets large when the population SD is large and when our sample size is small. We can make our estimates as precise as we want (small standard error) by increasing the size of the sample, that is, by using more participants in our research. N X σ σ = Descriptive vs. Inferential Statistics The mean and standard deviation can be used in 2 ways. One way is to describe the distribution of data (our mean is Xbar). The other way is to infer something about a population (is the population mean 25? 20?). A statistical test! Because the sampling distribution of the mean is normally distributed (Central Limit Theorem, but don’t worry about it), we can use the normal to show how close the parameter is likely to be to the sample mean and to make decisions about treatments. Statistical Tables There are several wellstudied statistical tables that are used for conducting statistical tests....
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 Spring '10
 Brannick
 Normal Distribution, Standard Deviation, Psychotherapy, Mean

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