How do i fix the error - the type 'system.windows.forms.control' is defined in an assembly that is not referenced

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Windows.Forms.DataVisualization.Charting;

namespace ARIMA_simulator
{
    class modelClass
    {
        private double random_normal() 
        {
            // this statement causes the error
            Chart a_chart;
            //
            double rand;
            a_chart = new Chart();
            rand = random_generator.NextDouble();
            rand = pStd
               * a_chart.DataManipulator.Statistics.InverseNormalDistribution(rand);
            a_chart = null;
            return rand;
        }
    }
}