How can I display the sum of each csv headers correctly when selected, it is adding up in the loop

  <table border="0" cellspacing="1" cellpadding="1" class="sortable" >

   <?php
      #read CSV file
      
      
    if (($handle = fopen("sample1.csv", "r")) !== FALSE)
        {
                        $mycsv = array();
                        while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) 
                        $mycsv[] = $data;
                        fclose($handle);
   
                    #Find the length of the transposed row
                      $row_length = count($mycsv);
                      echo "<form method='post' action=''><table><tr>";
                      echo "<th><input type='checkbox' onClick='toggle(this)' /> Select/Deselect All<br/>
                      </th>";
                      echo "<th>Column</th>";
                      echo "<th>Filter</th>";
                      echo "</tr>";

                      #Loop through each row (or each line in the csv) and output all the columns for that row
                     foreach($mycsv[0] as $col_num => $col)
                     {
          

                        echo "<tr>";                            
                        for($x=0; $x<1; $x++)
                        {
                                  
                          echo "<td><input type='checkbox' name='lang[]'  value='".$mycsv[$x][$col_num]."' ></td>";
                          echo "<td align='center'>"  .$mycsv[$x][$col_num]."</td>";
                          echo "<td>
                            <select name='method[]' >
                             <option value=''>Choose</option>
                              <option  value='sum'>Sum</option>
                              <option  value='mean'>Mean</option>              
                              <option  value='average'>Average</option>
                              <option  value='highest'>Highest Value</option>
                              <option  value='lowest'>Lowest Value</option>
                            </select>
                              </td>";
                          echo "</tr>";
                        }
          
                }
                          echo "<tr>";
                          echo "<td><input type='checkbox' name='lang[]' ></td>";
                          echo "<td align='center'><input type='text' name='own_column' placeholder='Type your new column here'><br></td>";
                          echo "<td><input type='text' name='own_column' placeholder='Own formula'><br></td>";
                          echo "</tr>";

                          //echo "<tr>";
                          //echo "<td colspan='3' align='center'><input type='submit' name='Order'/></td>";
                          //echo "</tr>";
                          echo "<tr>";
                          echo "<td colspan='3'><div class='wrapper'><br/><br/><input type='button' class='button' value='Input Button'>
                          </div></td>";
                          echo "</tr>
                          <tr><td><input type='submit' value='submit' name='submit'</td></tr><table></form>";

                    $post_data  = $_POST["lang"];
                    //$SelectedOption = $_POST['demo'];
                    for($i=0; $i < count($post_data); $i++)
                    {
                       //echo "Selected : " . $post_data[$i]."</br>" ;
                    } 
                       
                    $row_length = count($mycsv);
                    $col_length = count($post_data);
                    $flag = True;
                    $sum = array();
             
                    foreach ($mycsv[0] as $key => $value)
                    {
                        foreach ($post_data as $search_term) 
                        {

                            if (strcasecmp(trim($value), trim($search_term)) == 0) 
                            {

                                for ($row=0; $row < $row_length; $row++)
                                {
                                    
                                    array_push($sum,$mycsv[$row][$key]);

                                    if ($row == 0)
                                    {

                                        echo "<tr>";
                                        echo "<th colspan=100%>" . $mycsv[0][$key] . "</th>";
                                        echo "</tr>";
                                    }
                                    else if ($row == 1)

                                    {


                                       //echo "<td>" . $mycsv[$row][$key] . "</td>";
                                        //echo "array sum =".array_sum($sum)."";

                                    }  

                                           
                                //echo " array sum =".array_sum($sum)."] ";
                                
                                }

                                        $method = $_POST["method"];

                                        $method = $method[$key];
                                                                echo "<tr><td>";
                                                                if ($method == 'sum') {

                                                                                echo "Sum of " . $value;
                                                                                echo "array sum =".array_sum($sum)."";

                                                                }
                                                                else if ($method == 'mean') {
                                                                   echo "mean of " . $value;
                                                                }
                                                                else if ($method == 'average') {
                                                                   echo "average of " . $value;
                                                                }
                                                                else if ($method == 'highest') {
                                                                   echo "highest value of " . $value;
                                                                }else if ($method == 'lowest') {
                                                                   echo "lowest value of " . $value;
                                                                }else{
                                                                        echo " Choose a method ";
                                                                echo "</td></tr>";  
                                                                        }


                                                    
                                  }

                        }
                    }
        }

  ?>
</table>

As you can view in the image,After checking and choosing filter 'sum', the total sum of column year is 5 and sum of goods is 20, the sum of goods should have been 15, but it adds up with column year. How can I display them correctly.

After sum, I need to display the mean. average, highest and lowest of each. Am not able to display there answer seperately. Can someone solve this for me.Thank you.