Statistics/Chi-squared distribution: Difference between revisions

{{libheader|DOME}}

{{libheader|Wren-trait}}

{{libheader|Wren-plot}}

<syntaxhighlight lang="ecmascript">import "dome" for Window

import "graphics" for Canvas, Color

import "./math2" for Math

import "./trait" for Stepped

import "./plot" for Axes

System.print("χ2 cum pdf p-value")

Fmt.print(" χ2 value : $f", Chi2.pdf(dsum, dof))

Fmt.print(" p-value : $f", Chi2.cpdf(dsum, dof))

// generate points for plot

var Pts = List.filled(5, null)

for (k in 0..4) {

Pts[k] = []

var x = 0

while (x < 10) {

Pts[k].add([x, 10 * Chi2.pdf(x, k)])

x = x + 0.01

}

}

class Main {

construct new() {

Window.title = "Chi-squared distribution for k in [0, 4]"

Canvas.resize(1000, 600)

Window.resize(1000, 600)

Canvas.cls(Color.white)

var axes = Axes.new(100, 500, 800, 400, -0.5..10, -0.5..5)

axes.draw(Color.black, 2)

var xMarks = 0..10

var yMarks = 0..5

axes.mark(xMarks, yMarks, Color.black, 2)

var xMarks2 = Stepped.new(0..10, 2)

var yMarks2 = 0..5

axes.label(xMarks2, yMarks2, Color.black, 2, Color.black, 1, 10)

var colors = [Color.blue, Color.yellow, Color.green, Color.red, Color.purple]

for (k in 0..4) {

axes.lineGraph(Pts[k], colors[k], 2)

}

axes.rect(8, 5, 120, 110, Color.black)

for (k in 0..4) {

var y = 4.75 - k * 0.25

axes.line(8.2, y, 9, y, colors[k], 2)

y = 385 - k * 18

axes.print(750, y, k.toString, Color.black)

}

}

init() {}

update() {}

draw(alpha) {}

}

var Game = Main.new()</syntaxhighlight>

Terminal output:

χ2 cum pdf p-value

[[File:Wren_chisquared.png|thumb|center]]