OnTheFlyStats

One pass (O(N)) descriptive statistics including:

variance
means (arithmetic, geometric and RootMeanSquare)
sum, min & max
sample and population variance
standard deviation of sample and population
Range and mid range
Count (N)

Instead of writing:

var listMin = matrix[x].Min(); // TODO: calculate in one go
var listMax = matrix[x].Max(); // TODO: calculate in one go

Use:

var stats = matrix[x].Stats();
var listMin = stats.Min;
var listMax = stats.Max;

Instead of recalculating mean each time the loop updates:

foreach (var item in populationList)
{
    averageLabel.Value = populationList.Average(); // O(N * N) overhead, never write code like this
    minLabel.Value = populationList.Min(); // O(N * N) overhead, never write code like this
    maxLabel.Value = populationList.Max(); // O(N * N) overhead, never write code like this
}

Use:

var populationStats = new Stats();
foreach (var item in populationList)
{
    populationStats.Update(item);
    averageLabel.Value = populationStats.Average;
    minLabel.Value = populationStats.Min;
    maxLabel.Value = populationStats.Max;
}