PSYB07H3 Study Guide - Final Guide: Confidence Interval, Interval Estimation, Bias Of An Estimator
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2 is unknown, we must estimate 2 with s2 i. e. if you. If is known and don"t know the population variance use the sample variance to estimate. Because we use s, we can no longer declare the answer to be a z but rather it is a t. T table has critical values instead of t-values. Differences in formulas: m z x s m x s. To treat t as a z would give us too many significant results x t x. Therefore, for the student"s t distribution, we switch to the t-table when we use s2. For one-sample cases, degrees of freedom: df = n-1 for sample but if given , no need for n-1 just n. 1 df is lost because we used (sample mean) to calculate s2 (x-) = 0, all x can vary save for 1. N = 20 s = 6. 4: state the null and the alternative hypothesis.
