BU255 Study Guide - Final Guide: Confidence Interval, Probability Plot, Type I And Type Ii Errors
Document Summary
Evaluate the difference among the means of three or more populations. Examples: accident rates for 1st, 2nd, and 3rd shift, expected mileage for five brands of tires. Key assumptions: populations are normally distributed, populations have equal variances, samples are randomly and independently. All populations are equal: no variation in means among populations. At least one population mean is different: does not mean that all population means are different, some population pairs may be the same. Ha : at least one of the means is different from others. If all means are the same: the null hypothesis is not rejected. If at least one mean is different: the null hypothesis is rejected. Total variation can be split into two parts. Total variation (sst: aggregate dispersion of the individual data values across the various populations. Treatment (between-sample) variation (ssc: dispersion among the sample means. Error (within-sample) variation (sse: dispersion that exists among the data values within a particular population.
