Sample size is an important concept in statistics. In order to make reliable inferences of a population based upon a sample of that population, it is necessary to have a statistically significant sample size. One method of calculating the required sample size is Cochran's formula, named after the statistician William Gemmell Cochran.
Cochran's formula is as follows:
Here, p is the expected percent of the population with the desired attribute. e is the desired precision or margin of error. Z is something called the z-score, which is found in a z-score table (it's a statistics thing). In order to find the z-score, we must choose a desired confidence value (how confident are we in the results).
This recipe implements Cochran's formula for determining sample size in DAX based upon the chosen confidence levels, the proportion...
