Univariate inductive statistics - ordinal variable

Sign test

Sign test provides a hypothesis test for median of random sample. The null hypothesis specifies that median equals specified constant. The terminology, sign test, reinforces the point that the data are converted to a series of pluses and minuses. The test is based on the number of pluses that occur. Zero differences are thrown out, and the sample size is reduced accordingly. The quantile (sign) test is perhaps the oldest of all the nonparametric procedures. This nonparametric test is based on the binomial distribution.