Statistical Sciences 1024A/B Lecture Notes - Lecture 16: Science News, Clinical Trial, Sampling Distribution
20 Apr 2016
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Document Summary
If we know the standard deviation of the population, a confidence interval for the mean is: These are called z procedures because they both involve a one-sample z statistic and use the standard. The data must be an srs from the population (ask: where did the data come from?) Skewedness and outliers make the z procedures untrustworthy unless the sample is large. In practice, the z procedures are reasonably accurate for any sample of at least moderate size from a fairly symmetric distribution. The population standard deviation must be known: unfortunately, is rarely known, so z procedures are rarely useful, chapter 17 will introduce procedures for when is unknown. The assumption of a simple random sample or. The data can be plausibly thought of as observations taken at random from a population. Data are collected haphazardly with a selection bias of unknown effect (no valid confidence interval is.
