Glossary terms for 'Z'
| Z test | A statistical test used to compare proportions to determine if they are statistically significantly different from one another. Unlike the chi-squared test, which is always two-sided, the Z test can be used for one-sided hypotheses. For example, a one-sided Z test can be used to determine if the proportion of prisoners who have tattoos is significantly greater than the proportion of free-living persons who have them. In contrast, a two-sided Z test (or a chi-squared test) could be used to determine if the proportion of prisoners who have tattoos is significantly different (ie, smaller or larger) than the proportion not in prison who have them. |
Glossary material from Hulley SB et al. Designing Clinical Research, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2022.