Statistical Inference two types: 1. Estimating the value of a parameter with a confidence interval. 2. Assessing evidence for a claim about a parameter using a test of significance. We get Margin of Error (ME) from the sampling distribution of . Condition: 1. SRS(stratified, multistage are wrong!) 2.σ is known. 3. Sampling distribution of is normal. Level of confidence: the percentage of confidence intervals that could be produced by the procedure that actually contain the value of μ. Since the procedure of using ( -ME, +ME) to estimate μ gives intervals that contain μ for 95% of all possible values, we say: level of confidence is 95%. (Note: This can only be defined in terms of probability as follows: “The probability that the confidence interval to be computed (before data are gathered) will contain the value of the parameter.” After data are collected, level of confidence is no longer a probability because a calculated confidence interval either contains the value of the parameter or it doesn’t.) Multiple analyses: Performing two or more tests of significance on the same data set. This inflates/ amplifies the
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This note was uploaded on 02/27/2012 for the course STAT 121 taught by Professor Patticolling during the Winter '11 term at BYU.