variance property
The variance (i.e. square of the standard deviation) of the metric value.
If value is exact, variance is 0. Can be used to calculate margin of error as a percentage of value, using the following formula, where Z is the standard constant that depends on the desired size of the confidence interval (e.g. for 90% confidence interval, use Z = 1.645): marginOfError = 100 * Z * sqrt(variance) / value
Implementation
core.String? variance;