Bih weight of all 10 babies born in a nursing home on a day was 2.7 kg. Standard detion is –

**Core Concept**
The bih weight of a group of babies can be described by its mean and standard deviation. Standard deviation is a measure of the amount of variation or dispersion of a set of values from its mean value.

**Why the Correct Answer is Right**
To calculate the standard deviation of the birth weights, we can use the formula for sample standard deviation. However, with only one data point (mean birth weight of 2.7 kg), we cannot calculate the standard deviation directly. The correct answer suggests that the formula for population standard deviation (σ) is being used, which is √[(Σ(x - μ)^2)/N], where x is each individual data point, μ is the mean, and N is the total number of data points. But, since we are given only one value (mean), this is not applicable.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because the formula for sample standard deviation requires multiple data points, not just the mean.
**Option B:** This is incorrect because population standard deviation formula requires the data points, not just the mean.
**Option C:** This is incorrect because the given mean does not provide enough information to calculate the standard deviation.
**Option D:** This is incorrect because the formula for population standard deviation (σ) is not applicable with only one data point.

**Clinical Pearl / High-Yield Fact**
When dealing with small sample sizes, it's essential to understand the limitations of statistical calculations, such as standard deviation.

**Correct Answer: None. This is a trick question as we cannot calculate standard deviation with only one data point (the mean).**