Statistics > Nonparametrics > 1-Sample Sign Test Statistics > Nonparametrics > 1-Sample Sign Test This utility performs calculations for testing claims about a population median for the case when the type of population distribution cannot be assumed. The null hypothesis H0 of a claim is median = median0, where median0 is the hypothesized median. The alternative hypothesis H1 can be one of the following: median < median0, median > median0, or median ≠ median0. A sample value above median0 is assigned a positive (+) sign. A sample value below median0 is assigned a negative (-) sign. The test statistic is computed as follows: Left-tailed (H1: median < median0): s = the number of positive (+) signs Right-tailed (H1: median > median0): s = the number of negative (-) signs Two-tailed (H1: median ≠ median0): s = the minimum of the number of (+) signs and the number of (-) signs The p-value for a one-tailed test (left-tailed or right-tailed) is P(X ≤ s) where X is a random variable representing the number of positive signs. The p-value for a two-tailed test is 2P(X ≤ s). If the sample size n (excluding values that are equal to the hypothesized mean) is not more than 50, exact binomial probability calculations are used to compute the p-value. If the sample size is greater than 50, the normal distribution is used as an approximation to binomial: To use the utility, follow these steps: If individual samples are entered in a single column of the Datasheet, select the Samples in column: radio button, and select the column name in the drop-down menu. To use summary statistics of the sample data, select the Summarized sample data: radio button, and input the number of positive signs and the number of negative signs in the provided text fields. Select the form of the alternative hypothesis in the Alternative Hypothesis: drop-down menu. Enter the hypothesized population median in the provided text box. Click the OK button to perform the computation. The results will be displayed in the log window.