Hi Guy’s Welcome to Proto Coders Point. In this flutter dart programming article let’s understand what is mean variance & standard deviation & how to calculate them in dart programming language.

In data analysis, It’s is very crucial to understand the data tendency. ** mean, variance & standard deviation** are main statistical data measures.

## What is Mean, Variance & Standard deviation?

### Mean:

**Mean** is calculated by dividing sum of all the numbers in a given set (array)by the total number of numbers.

`Mean = (Sum of all the observations/Total number of observations)`

**Variance:**

Variance is calculated using mean of the squared differences from the average of the data set (array). It is a statistical measure that quantifies the amount of variability or dispersion within a dataset

`variance = s^2 = Σ(xi - x̅)^2 / (N - 1);`

**xi **= each value from the data set.**x̅** = Mean.**N **= Number of value in the data set.

**Standard Deviation:**

is calculated by square root of variance.

`SD = sqrt(variance)`

## Dart Program to find mean variance and standard deviation

Let’s calculate mean, variance & standard deviation using versatile programming language DART.

import 'dart:math'; void main() { List<double> data = [0.6, 1.2, 6, 3, 8, 11, 13, 8, 9.3, 9.4]; // Calculate the mean double mean = data.reduce((a, b) => a + b) / data.length; // Calculate the variance double variance = data.map((x) => pow(x - mean, 2)).reduce((a, b) => a + b) / (data.length - 1); // Calculate the standard deviation double standardDeviation = sqrt(variance); print('Mean: $mean'); print('Variance: $variance'); print('Standard Deviation: $standardDeviation'); }

`Mean: 6.95`

Variance: 17.402777777777782

Standard Deviation: 4.171663670261276