How do you describe the accurarcy and the precision of a given data set?

Find the variance (accuracy) Take the numbers from the stet and subtract the mean value of the data set from each one. Square each of those and add them together. Divide by the number of values you have - 1.

To find Precision you take the standard deviation (The square root of the variance) from the set measurements and divide it by the square root of the number samples.