A random sample of 64 healthy adults has a mean serum iron level of 95 microgram/dL with a standard deviation of 16 microgram/dL. The standard error of the mean is:

• A 16 microgram/dL
• B 4 microgram/dL
• C 2 microgram/dL ✓
• D 8 microgram/dL

Explanation

Standard error of the mean (EM) = SD / square root of n = 16 / sqrt(64) = 16 / 8 = 2 microgram/dL. EM quantifies the precision of the sample mean as an estimate of the population mean, not the variability of individual observations (which is what SD measures). Confusing SD with SE is a common error in interpretation.

Reference: B K Mahajan's Methods in Biostatistics, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.