Goal: Calculate Volatility (Standard Deviation).
How far, on average, are the points from the center (Mean)?
1. Find Mean →
2. Measure Dist →
3. Square & Avg →
4. Root
Ready...
💻 Formula Structure
=STDEV.P(number1, ...)
- Logic: Use when you have ALL the data (Population).
- Math: Divides by N (Total count).
=STDEV.S(number1, ...)
- Logic: Use when you only have a SUBSET (Sample).
- Math: Divides by N - 1 (Bessel's Correction). Results in a larger spread.
⚠️ Common Pitfalls
🚫 Old Function
STDEV (without dot) is the old version of STDEV.S. It still works, but Microsoft recommends the new versions.
🚫 P vs S
Most real-world data is a Sample (STDEV.S). Only use Population (STDEV.P) if you have 100% of the data points available.