EXAMPLE 6.23 More on Information Provided by the -Value

We have a test statistic of for a two-sided significance test on a population mean. Software tells us that the -value is 0.000003. This means that there are three chances in 1,000,000 of observing a sample mean this far or farther away from the null hypothesized value of . This kind of event is virtually impossible if the null hypothesis is true. There is no ambiguity in the result; we can clearly reject the null hypothesis.