MATH 116 Lecture Notes - Lecture 4: Normal Distribution, Simple Random Sample, Point Estimation
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Mat 121: elementary probability and statistics- lecture 17: t-distributions. Review: we use simple mean x-bar" to construct a con dence interval (ci) to estimate a population mean ". Such interval has the equation- (x-bar-e < < x-bar+e: the sample mean x-bar" is best best point estimate of the population mean ", the cl= = 1- cl. Find the t-scores t. 025, if df= 29: row= df= 29 t-score= 2. 045 t. 005, if df= 36, row= df= 36. Column= right area= = . 025: find the intersection of the row and column in table a-3. Column= right area= = . 005: find the intersection of the row and column in table a-3 t-score= 2. 719. Con dence interval: requirement, if is known, sample is simple random sample, population is normally distributed or the sample size is n > 30. E= z( /2) * ( / n) z( /2) = z-score for which the right area is ( /2) = population standard deviation: if is unknown-
