Apr 11, 2018
Can you help me with standard deviation where there is more than 20 numbers? I'm failing math.
How do we compute standard deviation?
We use
where s is the sample standard deviation (what we want to find), X is your numbers / samples / values, X with a bar is the sample mean, and n is your amount of samples.
I’ll break it up into steps for you:
1. find the sample mean. Mean = X with a bar = (sum of all values)/(amount of values)
2. compute (X - X with a bar)^2 for each of your numbers / samples / values
3. sum all (X - X with a bar)^2
4. divide by n - 1
5. take the square root
Please let us know if you have a more detailed question or want an example! Try it, it’s not too difficult.
- Kendra