This is the currently selected item. For a given set of observations the arithmetic mean can be calculated by adding all the observations and dividing the value obtained by the number of observations. Add all the data points together then divide by the number of data points.
Lets say you take 10 samples from here and you get 92 when you find their mean.
The standard formula for sample size is. The sample mean is represented by x bar. The sample mean is the average of all the items in a sample a group of observations. Add up the sample items.