Statistics: signtest

### Function Reference: `signtest`

statistics: [pval, h, stats] = signtest (x)
statistics: [pval, h, stats] = signtest (x, m)
statistics: [pval, h, stats] = signtest (x, y)
statistics: [pval, h, stats] = signtest (x, y, Name, Value)

Test for median.

Perform a signtest of the null hypothesis that x is from a distribution that has a zero median. x must be a vector.

If the second argument m is a scalar, the null hypothesis is that X has median m.

If the second argument y is a vector, the null hypothesis is that the distribution of `x - y` has zero median.

The argument `"alpha"` can be used to specify the significance level of the test (the default value is 0.05). The string argument `"tail"`, can be used to select the desired alternative hypotheses. If `"tail"` is `"both"` (default) the null is tested against the two-sided alternative `median (x) != m`. If `"tail"` is `"right"` the one-sided alternative `median (x) > m` is considered. Similarly for `"left"`, the one-sided alternative `median (x) < m` is considered.

When `"method"` is `"exact"` the p-value is computed using an exact method. When `"method"` is `"approximate"` a normal approximation is used for the test statistic. When `"method"` is not defined as an optional input argument, then for `length (x) < 100` the `"exact"` method is computed, otherwise the `"approximate"` method is used.

The p-value of the test is returned in pval. If h is 0 the null hypothesis is accepted, if it is 1 the null hypothesis is rejected. stats is a structure containing the value of the test statistic (sign) and the value of the z statistic (zval) (only computed when the ’method’ is ’approximate’.

Source Code: signtest