Test Mean

Use the Test Mean option in the Distribution platform to specify options for and perform a one-sample test for the mean. If you specify a value for the standard deviation, a z test is performed. Otherwise, the sample standard deviation is used to perform a t test. You can also request the nonparametric Wilcoxon Signed-Rank test.

You can use the Test Mean option repeatedly to test different values. Each time you test the mean, a new Test Mean report appears.

Description of the Test Mean Report

Statistics That Are Calculated for Test Mean

t Test (or z Test)

Lists the value of the test statistic and the p-values for the two-sided and one-sided alternatives.

Signed-Rank

(Appears only if the Wilcoxon Signed-Rank test is selected.) Lists the value of the Wilcoxon signed-rank statistic followed by p-values for the two-sided and one-sided alternatives. The test uses the Pratt method to address zero values. This is a nonparametric test whose null hypothesis is that the median equals the postulated value. It assumes that the distribution is symmetric. See Statistical Details for the Wilcoxon Signed Rank Test.

Probability Values

Prob > |t|

The probability of obtaining an absolute t value that is greater than the observed t value when the population mean is equal to the hypothesized value. This is the p-value for observed significance of the two-tailed t test.

Prob > t

The probability of obtaining a t value greater than the computed sample t ratio when the population mean is not different from the hypothesized value. This is the p-value for an upper-tailed test.

Prob < t

The probability of obtaining a t value less than the computed sample t ratio when the population mean is not different from the hypothesized value. This is the p-value for a lower-tailed test.

Descriptions of the Test Mean Options

PValue animation

Starts an interactive visual representation of the p-value. Enables you to change the hypothesized mean value while watching how the change affects the p-value.

Power animation

Starts an interactive visual representation of power and beta. You can change the hypothesized mean and sample mean while watching how the changes affect power and beta.

Remove Test

Removes the mean test.

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