Microsoft Visual C# Example Application: Measures of Center

In statistics-related calculations, we consider two categories of values:

• A population is the a collection of all values based on the items considered. They can be people, insects, cars, students
• A sample is a sub-collection derived from a population

1. Start Microsoft Visual Studio
2. To create a new application, on the main menu, click File -> New Project...
3. In the middle list, click Windows Forms Application
4. Change the Name to MeasuresOfCenter
5. Click OK
6. In the Solution Explorer, right-click Form1.cs and click Rename
7. Type Measures.cs and press Enter
8. Design the form as follows:
    

   Control Name Text Label   Value (x): TextBox txtValue   Button btnAdd Add ListBox lbxValues   Button btnClear Clear Label   Sum: TextBox txtSum   Label   Mean: TextBox txtMean   Label   Median: TextBox txtMedian   Label   Midrange: TextBox txtMidrange   Label lblCount Number of Values: Button btnClose Close

9. Double-click an unoccupied area of the form
10. Change the file as follows:

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;
    
    namespace MeasuresOfCenter
    {
        public partial class Measures : Form
        {
            List<double> values;
    
            public Measures()
            {
                InitializeComponent();
            }
    
            private void Measures_Load(object sender, EventArgs e)
            {
                values = new List<double>();
            }
    
            void ShowValues()
            {
                lbxValues.Items.Clear();
    
                for (int i = 0; i < values.Count; i++)
                    lbxValues.Items.Add(values[i]);
    
                lblCount.Text = values.Count.ToString();
            }
        }
    }

11. Return to the form
12. Double-click the Clear button
13. Implement its event as follows:

    private void btnClear_Click(object sender, EventArgs e)
    {
        values.Clear();
        lbxValues.Items.Clear();
    
        txtValue.Text = "";
        txtSum.Text = "";
        txtMean.Text = "";
        txtMedian.Text = "";
        txtMidrange.Text = "";
        txtValue.Focus();
    }

14. Return to the form

1. Double-click the Add button
2. Implement its event as follows:

   private void btnAdd_Click(object sender, EventArgs e)
   {
       // This the value that will be added to the text box
       double value = 0.00;
       double sum = 0.00, mean = 0.00;
   
       // Check that the user entered a value in the text box
       if (txtValue.Text.Length == 0)
       {
           MessageBox.Show("You must enter a value.", "Measures of Center");
           return;
       }
   
       try
       {
           // Get the value the user entered
           value = double.Parse(txtValue.Text);
           // Add it to the collection
           values.Add(value);
           // Show the values in the list box
           ShowValues();
   
           txtValue.Text = "";
           txtValue.Focus();
       }
       catch (FormatException)
       {
           MessageBox.Show("The value you entered is invalid.",
                           "Probability Distribution");
       }
   
       // Calculate the total
       for (int i = 0; i < values.Count; i++)
           sum += values[i];
       // Calculate the mean
       mean = sum / values.Count;
   
       // Display the values
       txtSum.Text = sum.ToString("F");
       txtMean.Text = mean.ToString("F");
   }

3. To execute, press F5
4. Type each of the following values and click Add after each: 72604, 7592, 6314, 57086, 24885
    
   
    
   
5. Close the form and return to your programming environment

The median is the value in the middle of a collection but it follows these three rules:

• First sort the values in the collection
• If the number of values in the collection is odd, the median is the value in the middle
• If the number of values in the collection is even, the median is the mean of the middle two values

1. Change the code of the Add button as follows:

   private void btnAdd_Click(object sender, EventArgs e)
   {
       // This the value that will be added to the text box
       double value = 0.00;
       double sum = 0.00, mean = 0.00;
       double median = 0.00;
   
       // Check that the user entered a value in the text box
       if (txtValue.Text.Length == 0)
       {
           MessageBox.Show("You must enter a value.", "Measures of Center");
           return;
       }
   
       try
       {
           // Get the value the user entered
           value = double.Parse(txtValue.Text);
           // Add it to the collection
           values.Add(value);
           // Show the values in the list box
           ShowValues();
   
           txtValue.Text = "";
           txtValue.Focus();
       }
       catch (FormatException)
       {
           MessageBox.Show("The value you entered is invalid.",
                           "Probability Distribution");
       }
   
       // Calculate the total
       for (int i = 0; i < values.Count; i++)
           sum += values[i];
       // Calculate the mean
       mean = sum / values.Count;
   
       // Get ready to evaluate the median
       // First sort the list
       values.Sort();
   
       // Find out if the list is odd
       if ((values.Count % 2) == 0)
       {
           double midIndex = values.Count / 2;
           median = (values[(int)(midIndex - 0.5)] +
           	  values[(int)(midIndex + 0.5)]) / 2;
       }
       else
           median = values[values.Count / 2];
   
       // Display the values
       txtSum.Text = sum.ToString("F");
       txtMean.Text = mean.ToString("F");
       txtMedian.Text = median.ToString("F");
   }

2. To execute, press F5
3. Type each of the following values and click Add after each: 72604, 7592, 6314, 57086, 24885
    
   
4. Close the form and return to your programming environment

The midrange is the mean of the minimum and the maximum values of a collection. Obviously, the collection should be sorted.

1. Change the code of the Add button as follows:

   private void btnAdd_Click(object sender, EventArgs e)
   {
       // This the value that will be added to the text box
       double value = 0.00;
       double sum = 0.00, mean = 0.00;
       double median = 0.00, midrange = 0.00;
   
       // Check that the user entered a value in the text box
       if (txtValue.Text.Length == 0)
       {
           MessageBox.Show("You must enter a value.", "Measures of Center");
           return;
       }
   
       try
       {
           // Get the value the user entered
           value = double.Parse(txtValue.Text);
           // Add it to the collection
           values.Add(value);
           // Show the values in the list box
           ShowValues();
   
           txtValue.Text = "";
           txtValue.Focus();
       }
       catch (FormatException)
       {
           MessageBox.Show("The value you entered is invalid.",
                           "Probability Distribution");
       }
   
       // Calculate the total
       for (int i = 0; i < values.Count; i++)
           sum += values[i];
       // Calculate the mean
       mean = sum / values.Count;
   
       // Get ready to evaluate the median
       // First sort the list
       values.Sort();
   
       // Find out if the list is odd
       if ((values.Count % 2) == 0)
       {
           double midIndex = values.Count / 2;
           median = (values[(int)(midIndex - 0.5)] +
           	values[(int)(midIndex + 0.5)]) / 2;
       }
       else
           median = values[values.Count / 2];
   
       // Calculate the midrange as the mean between the minimum and maximum
       midrange = (values[0] + values[values.Count-1]) / 2;
   
       // Display the values
       txtSum.Text = sum.ToString("F");
       txtMean.Text = mean.ToString("F");
       txtMedian.Text = median.ToString("F");
       txtMidrange.Text = midrange.ToString("F");
   }

2. Return to the form
3. Double-click the Close button
4. Implement its event as follows:

   private void btnClose_Click(object sender, EventArgs e)
   {
       Close();
   }

5. To execute, press F5
6. Type each of the following values and click Add after each: 72604, 7592, 6314, 57086, 24885
    
   
   
7. Close the form and return to your programming environment

Application