In a study of 200 patients with hypertension, the mean systolic blood pressure is 148 mmHg with a standard deviation of 12 mmHg. A researcher wants to test whether this mean differs from the population mean of 145 mmHg. Which test is MOST appropriate?

• A Chi-square test
• B Mann-Whitney U test
• C Kruskal-Wallis test
• D One-sample z-test ✓

Explanation

A one-sample z-test is used to compare a sample mean against a known population mean when the sample size is large (n ≥ 30) and the population standard deviation is known or estimated. With n=200 and continuous normally distributed data, this is the correct parametric test. Chi-square is for categorical data; Mann-Whitney and Kruskal-Wallis are non-parametric tests for comparing groups.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.