**Question:** Birth weight of all 10 babies born in a nursing home on a day was 2.7 kg. Standard deviation is -

A. 0.84 kg
B. 0.32 kg
C. 0.45 kg
D. 0.5 kg

**Correct Answer:** B. 0.32 kg

**Core Concept:** Standard deviation (SD) is a measure of the dispersion or spread of a set of data around the mean. In this case, the data are the birth weights of the babies.

**Why the Correct Answer is Right:** The correct answer (0.32 kg) represents the standard deviation of the birth weights of the babies. It shows the average distance of each birth weight from the mean (2.7 kg). A smaller standard deviation indicates a more concentrated distribution of birth weights around the mean.

**Why Each Wrong Option is Incorrect:**

A. 0.84 kg - This value is too large, suggesting a more dispersed distribution of birth weights around the mean.
C. 0.45 kg - This value is too small, indicating a more concentrated distribution of birth weights around the mean.
D. 0.5 kg - This value is too large, similar to option A.

**Clinical Pearl:** Understanding standard deviation helps clinicians interpret the distribution of patient data (e.g., vital signs, laboratory values, or medical interventions) and make informed decisions based on the variability or consistency of these values. In this scenario, a smaller standard deviation is desirable for birth weights, meaning that Option B (0.32 kg) is the correct answer as it represents a more consistent distribution of birth weights around the mean.