The two-sample t-test is one of the most commonly used hypothesis tests in Six Sigma work. It is applied to compare the average difference between two groups. You use it to determine if the difference ...

At times we wish to examine statistical evidence, and determine whether it supports or contradicts a claim that has been made (or that we might wish to make) concerning the entire population. This is ...

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Stein [4] has exhibited a double sampling procedure to test hypotheses concerning the mean of normal variables with power independent of the unknown variances. This procedure is here adapted to test ...