# Basic standard deviation calculation

• I
• Graham87
In summary, standard deviation calculation is a statistical measure that shows the variability of data in a dataset. Its formula involves finding the square root of the sum of squared differences between each data point and the mean, divided by the number of data points. Standard deviation is important because it helps us understand the spread of data and make comparisons between different datasets. It can also be used to interpret the range of values within which most data points fall. Standard deviation is commonly used in science, finance, and social sciences for data analysis, trend identification, and prediction.

#### Graham87

I don’t get how they got the equation for the standard deviation. Why do they only square with the time in the denominator?

Thanks!

We know that the SD of the total number of counts n is √n and rate r =n/t

So;
n=rt
Δn = (Δr)⋅t =√(n/t)t
Δr=√(n)/t =√(n/t2)

Graham87
gleem said:
We know that the SD of the total number of counts n is √n and rate r =n/t

So;
n=rt
Δn = (Δr)⋅t =√(n/t)t
Δr=√(n)/t =√(n/t2)
Aha! Thanks!