What is variance and how is it different from standard deviation?

Problem Statement

What is variance and how is it different from standard deviation?

Step-by-Step Explanation

Variance measures average squared spread, while standard deviation is its square root and uses the original units.

1. Identify what the question is asking. In Statistics, this usually means naming the known quantities, the unknown quantity, and the concept that connects them.
2. Write the relevant definition, rule, or relationship before substituting numbers or manipulating symbols.
3. Work one step at a time and keep units, signs, and restrictions visible.
4. Check whether the answer makes sense in the original context.

Final Answer

Variance measures average squared spread, while standard deviation is its square root and uses the original units. The reliable strategy is to start from the definition, apply the correct rule carefully, and then interpret the result in plain language.