how do i set up data to find the standard deviation of the data?
first you need the mean
Xmean =sum of all points/number of points
then you need a list of differences from mean
(Xi-Xmean)
some will be - and some +
then square the values in that list
(Xi-Xmean)^2
divide by (n-1) one less than number of points
take the square root
check out:
http://www.easycalculation.com/statistics/learn-standard-deviation.php
To calculate the standard deviation of a set of data, you will need to follow these steps:
1. Collect the data: Gather the set of values for which you want to find the standard deviation. Ensure that the data is complete, accurate, and relevant to the analysis you are conducting.
2. Calculate the mean: Add up all the values in the data set and divide the sum by the total number of values. This will give you the mean or average of the data set.
3. Calculate the differences: Subtract the mean from each individual data point. These differences represent the deviations from the mean.
4. Square the differences: For each deviation, square the result. This step is necessary to avoid negative values and to give more weight to larger deviations.
5. Calculate the variance: Add up all the squared deviations and divide the sum by the total number of data points. This will give you the variance of the data set.
6. Find the square root: Take the square root of the variance value calculated in the previous step. This will give you the standard deviation, which measures the dispersion or spread of the data.
It's worth noting that there are various formulae for the sample standard deviation and population standard deviation, depending on whether you are working with a sample of data or the entire population. The above steps outline the commonly used technique for sample standard deviation.