One Proportion Z Test is a hypothesis test in statistics to compare a group to specified population proportion. Hypothesis test requires an analyst to state a null hypothesis and an alternative hypothesis. The hypothesis are stated in a way that they are mutually exclusive, means if one is true, the other one must be false and vice versa. Use this hypothesis z test one population proportion statistics calculator to calculate the Z - test statistic value for the given population proportion, sample size and null hypothesis value.