Calcolatore Deviazione Standard
Calcola la deviazione standard di tre valori. Include varianza e media.
Media
20.0000
Formula
Standard Deviation
Formula
Population SD = sqrt(sum of (xᵢ - mean)² / N)
Sample SD = sqrt(sum of (xᵢ - mean)² / (N-1))
Steps
1. Calculate the mean (average) 2. Find each value's deviation from the mean 3. Square each deviation 4. Average the squared deviations (divide by N for population, N-1 for sample) 5. Take the square root
Esempio Risolto
Find the standard deviation of 10, 20, 30.
- 01Mean = (10+20+30)/3 = 20
- 02Deviations: -10, 0, +10
- 03Squared: 100, 0, 100
- 04Variance = (100+0+100)/3 ≈ 66.67
- 05Std Dev = √66.67 ≈ 8.1650
Domande Frequenti
What is standard deviation?
Standard deviation measures the spread or dispersion of data points from the mean. A low SD means data clusters near the mean; a high SD means data is more spread out.
When do I use population vs sample?
Use population SD (divide by N) when you have data for the entire population. Use sample SD (divide by N-1) when your data is a sample from a larger population.
What is variance?
Variance is the average of squared deviations from the mean. Standard deviation is the square root of variance, bringing the units back to the original scale.
Impara