Returns the confidence interval for a population mean, using a normal distribution.
The significance level used to compute the confidence level. The confidence level equals 100*(1 – alpha)%, or in other words, an alpha of 0.05 indicates a 95 percent confidence level.
The population standard deviation for the data range and is assumed to be known.
The sample size.
The confidence interval is a range of values. Your sample mean, x, is at the center of this range and the range is x ± CONFIDENCE.NORM. For example, if x is the sample mean of delivery times for products ordered through the mail, x ± CONFIDENCE.NORM is a range of population means.
Contributors: Alberto Ferrari, Marco Russo
MSDN documentation: https://msdn.microsoft.com/en-us/query-bi/dax/confidence-norm-function-dax