# Mean for population standard deviation for that

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: mean for population : standard deviation for that population Statistic: xx̅: sample mean s=standard deviation s .d(´x)=σn(how far xx̅ is from ) Standard deviation of sample mean(s.d (xx̅)) is approximately the average distance of the possible sample mean values (for repeated samples of the same size n) from the true population mean Standard error:s .e(´x)=snestimate of the standard deviation of xx̅: estimating, approximately the average distance of the possible xx̅ values (for a repeated sample of the same size n) from the true population mean DISTRIBUTIONS Parent population has normal possible values of xx̅ is also normalIf parent is not normal + sample size is 25 then by the CENTRAL LIMIT THEOREM (CLT), xx̅ sample values will also be normalt(n-1) distributions The sample distribution of a statistics is the distribution of the statistic value if repeated random samples areobtainedCONFIDENCE INTERVAL FOR POPULATION MEAN N(,n)Confidence interval: ´xts.ex)Assumptions for interval:
1)random sample from a normal distributionInterpretations: Interval:With __% confidence, we estimate the population mean (context) to be between ____ and ____ Level:If we repeat this procedure many times, we expect that __% of the resulting intervals to contain the population mean (context)