The Variance (Variance) (var) is a measurement of the spread between numbers in a data set relative to its mean. Variance is always non-negative: a small variance indicates that the data points tend to be very close to the mean value and hence to each other, while a high variance indicates that the data points are very spread out around the mean and from each other.

Calculation

In the case of a set of N values Specification 029 and the arithmetic mean Specification 027 , the sample (unbiased) variance is

Variance 001

The population variance is differ only in division factor:

Variance 002

Chart Example

Implementation and Usage

To initialize indicator, use one of the following constructors:

Variance – set default values: period = 14

Variance(Int32, Boolean) – set value for period

Variance(TimeSpan, Boolean) – sets time period

Use

Var - property to get current value

Example

Copy

 1// Create new instance
 2var indicator = new Variance(28);
 3
 4// Number of stored values
 5indicator.HistoryCapacity = 2;
 6
 7// Add new data point
 8indicator.Add(CurrentPrice);
 9
10// Get indicator value
11double IndicatorValue = indicator.Var;
12// Get previous value
13if (indicator.HistoryCount == 2)
14{
15    double IndicatorPrevValue = indicator[1];
16}