chap 9 terms

chap 9 terms - free to vary when computing SS for sample...

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Chapter 9 New Terms and Concepts The following terms were introduced in this chapter. You should be able to define or describe each term and, where appropriate, describe how each term is related to other terms on the list. t statistic: A statistic used to summarize sample data in situations where the population standard deviation is not known. The t statistic is similar to a z-score for a sample mean, but the t statistic uses an estimate of the standard error. estimated standard error: An estimate of the standard error that uses the sample variance (or standard deviation) in place of the corresponding population value. degrees of freedom(df): Degrees of freedom = df = n - 1, measures the number of scores that are
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Unformatted text preview: free to vary when computing SS for sample data. The value of df also describes how well a t statistic estimates a z-score. t distribution: The distribution of t statistics is symmetrical and centered at zero like a normal distribution. A t distribution is flatter and more spread out than the normal distribution, but approaches a normal shape as df increases. (r2 ) the percentage of variance accounted for: A measure of effect size that determines what portion of the variability in the scores can be accounted for by the treatment effect....
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