Team 1 has 3 good shots. Team 2 has 20 bad shots. Both total an xG of 1. Who wins? - Sample result: {:win=>35710, :tie=>31614, :lose=>32676}

XGsimulation.rb

#!/bin/ruby

def generate_game(team_1_shots, team_2_shots)
  score1 = (team_1_shots.map { |x| if rand < x then 1 else 0 end }).inject(:+)
  score2 = (team_2_shots.map { |x| if rand < x then 1 else 0 end }).inject(:+)
  return [score1,score2]
end

def evaluate(game)
  if game[0] > game[1]
    :win
  elsif game[0] == game[1]
    :tie
  else
    :lose
  end
end

results = {:win => 0, :tie => 0, :lose => 0}

games = []
sims = 10000
scores = {}
team_1_shots = [0.05,0.05,0.05,0.05,0.05,0.05,0.05,0.05,0.05,0.05,0.05,0.05,0.05,0.20,0.20,0.20]
team_2_shots = [0.6,0.6]
sims.times.each do |game|
  game = generate_game(team_1_shots, team_2_shots)
  results[evaluate(game)] += 1
  if scores["#{game[0]}-#{game[1]}"]
    scores["#{game[0]}-#{game[1]}"] = scores["#{game[0]}-#{game[1]}"] += 1
  else
    scores["#{game[0]}-#{game[1]}"] = 1
  end
end

puts "Team 1 xG: #{team_1_shots.inject(:+)}"
puts "Team 2 xG: #{team_2_shots.inject(:+)}"
puts "Team 1 Wins: #{results[:win]}, Ties: #{results[:tie]}, Team 2 Wins: #{results[:lose]}"
#Reenable this to show each score-line. 
#puts Hash[scores.sort_by{|k, v| v}.reverse]
puts "Team 1 PPG: #{(results[:win]*3.0+results[:lose])/sims}"
puts "Team 2 PPG: #{(results[:lose]*3.0+results[:lose])/sims}"