PSYC 60 Chapter Notes - Chapter 10: Standard Deviation, Pooled Variance, Variance
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Independent measures: two sets of data come from two completely separate groups of participants; between subjects. Repeated-measures: two sets of data could come from same group of participants; within-subjects. 10. 2 the t-statistic for an independent measures research design t = Goal: evaluate the mean difference between two populations. Numerator of t statistic difference actually exists vs denominator how much. Two sample t that doubles all the elements of the single sample t formulas difference should exist between two sample means if there is no treatment effect. Variance obtained from large sample more accurate estimate of 2. Pooled variance: combine two sample variances into a single value. Large percentage produce a wider interval width of interval depends on sample size larger sample narrower interval. Independent measures t: size of difference between the two sample means. Larger mean difference increase chance of rejecting null hypothesis. Size of samples (affect standard error in denominator)
