STATS 250 Study Guide - Midterm Guide: Unimodality, Type I And Type Ii Errors, Standard Deviation
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STATS 250 Full Course Notes
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T distribution: used to infer about population means, symmetrical, unimodal, centered at 0, flatter and heavier tails compared to n(0,1, as df increased the t distribution approaches the n(1,0) distribution. Check if: x is the sample mean for a random sample, and the original population follows normal model or the population size is large enough: use qq plot to see if data is normal. When using t table: use df --- n-1, always use smaller df if it is not on the table, when the t* gets larger it approaches z* Creating confidence interval to estimate the population mean: x +/- t* (s/ n, t* from table. Interesting interval: with __% confidence, we would estimate the population mean ______at which all ______ to be between _____ and ______ Interpreting confidence level: if we repeat this study many times we would expect the population mean ______ of all _____ to be in ___% of the resulting intervals.