need help calculating an average

badgirlkelly · #1 02-04-2010, 08:29 PM

Hi

Can anyone help me try and sort this out please

the idea here is to find out the average height out of the three backs of numbers

height 15,16,17,18,19
number of 4,5,11,10,6
then i have to multiply them which gives me
60,80,187,180,114

here is the maths side of it

Total of height 60+80+187+180+114= 621
Total of number 4+5+11+10+6 = 36

621/36= 17.25

Average height is 17.25cm

what i am trying to do is get the script to give me the average height. been trying for a while now but all i get is

Quote:

< The average of the plants 60,80,187,180,114 is 0

anyone help this poor girl stop getting tormented by the script from hell

and give me my life back

love
kelly
xxx

Code:

<<HEAD>
<TITLE>
averages
</TITLE>

<SCRIPT LANGUAGE = "JavaScript">
 

//Experimental results of Table 1 stored in arrays.
var height = [15,16,17,18,19];
var number = [4,5,11,10,6];

//Part (ii).
//Write code to declare and initialise new array to represent the third row of the table.
var myarray = new Array(5)
var myarray = ["60","80","187","180","114"] ;

//Part  (iv).
//Write code to calculate the average height and write it out in the browser window.
var values = [60, 80, 187, 180, 114];
var total = 0;

for ( var i = 0; i < values.length; ++i)
var averageDivisor = 0;

for (var i = 0; i < number.length; i++)
     averageDivisor += number[i];

var myarray = total / averageDivisor;


document.write("The average height " + values.join(",") + " is " + myarray);

</SCRIPT>

</HEAD>
<BODY>
</BODY>
</HTML>

*coothead* · #2 02-05-2010, 07:21 PM

Hi there badgirlkelly,

and a warm welcome to these forums.

Have a look at this example, hopefully, it may give you your life back

Code:


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="language" content="english"> 
<meta http-equiv="Content-Style-Type" content="text/css">
<meta http-equiv="Content-Script-Type" content="text/javascript">

<title></title>

<style type="text/css">
form {
    width:270px;
    padding:20px;
    border:3px double #999;
    margin:auto;
 }
form h1 {
    margin-bottom:20px;
    font-size:16px;
    text-align:center;
 }
form div {
    height:25px;
    margin-bottom:8px;
    vertical-align:top;
 }
form select{
    display:none;
 }
</style>

<script type="text/javascript">

function calculate(){ 

  document.forms[0].reset();

  s=[];
  op=[];
  hgt=[];
  num=[];
  totalHeight=[];
  totalNumber=[];

for(k=0;k<6;k++) {
   s[k]=document.createElement('select');
   for(c=0;c<21;c++) {
   op[c]=document.createElement('option');
   op[c].setAttribute('value',c);
   op[c].appendChild(document.createTextNode(c))
   s[k].appendChild(op[c]);
 }
  document.getElementById('d'+k).appendChild(s[k]);
 }
  cb=document.forms[0].getElementsByTagName('input');
  sel=document.forms[0].getElementsByTagName('select');

for(c=0;c<cb.length;c++){
if(cb[c].type=='checkbox') {
   hgt[c]=0;
   num[c]=0;
   totalHeight[c]=0;
   totalNumber[c]=0;
   cb[c].number=c;
   sel[c].number=c;

cb[c].onclick=function(){ 
if(this.checked==true){
   sel[this.number].style.display='inline';
   hgt[this.number]=parseFloat(this.value);
 }
else {
   sel[this.number].style.display='none';
   hgt[this.number]=0;
  }
 }

sel[c].onchange=function(){
    num[this.number]=parseFloat(this.value);
    totalHeight[this.number]=num[this.number]*hgt[this.number]
    totalNumber[this.number]=num[this.number];
   }
  }
 }

document.getElementById('calc').onclick=function() {
   th=0;
   tn=0;
for(c=0;c<totalHeight.length;c++) {
   th+=parseFloat(totalHeight[c]);
   tn+=parseFloat(totalNumber[c]);
 }
   av=th/tn;
if(isNaN(av)) {
   av=0;
 }
   document.getElementById('result').firstChild.nodeValue='The average height is '+av.toFixed(2)+'cms';
  }


document.getElementById('res').onclick=function() {
   document.getElementById('result').firstChild.nodeValue='';
for(c=0;c<sel.length;c++) {
if(sel[c].style.display=='inline') {
   sel[c].style.display='none';
   hgt[c]=0;
   num[c]=0;
   totalHeight[c]=0;
   totalNumber[c]=0;
    }
   }
  }
 }

if(window.addEventListener){
   window.addEventListener('load',calculate,false);
 }
else { 
if(window.attachEvent){
   window.attachEvent('onload',calculate);
  }
 }
</script>

</head>
<body>

<form action="#">
<h1>average height calculator</h1>
<div id="d0">
<label for="c0">15cms :</label><input id="c0" type="checkbox" value="15">
</div>

<div id="d1">
<label for="c1">16cms :</label><input id="c1" type="checkbox" value="16">
</div>

<div id="d2">
<label for="c2">17cms :</label><input id="c2" type="checkbox" value="17">
</div>

<div id="d3">
<label for="c3">18cms :</label><input id="c3" type="checkbox" value="18">
</div>

<div id="d4">
<label for="c4">19cms :</label><input id="c4" type="checkbox" value="19">
</div>

<div id="d5">
<label for="c5">20cms :</label><input id="c5" type="checkbox" value="20">
</div>

<div>
<input id="calc" type="button" value="calculate">
<input id="res" type="reset" value="clear">
</div>

<div id="result">&nbsp;</div>
</form>

</body>
</html>

coothead

badgirlkelly · #3 02-05-2010, 08:14 PM

Hi

Thanks for the help

i have now got it working

thanks
kelly

*coothead* · #4 02-05-2010, 08:17 PM

No problem, you're very welcome.