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Thread: array

10182008, 03:27 PM #1
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array
resolved
Last edited by flouriet; 10202008 at 12:31 PM. Reason: resolved
10182008, 04:40 PM
#2
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Sounds like homework! Have a look at the posting guidlines.
Show us your effort, and then perhaps someone will help you improve it.
Quizmaster. Who was the Roman god of war? I'll give you a clue. It is the name of a type of chocolate bar.
Contestant: Twix.
10192008, 06:58 PM
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I get very confused with this stuff, is there any recommended books that I can read to help me. thhanks
10192008, 09:02 PM
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Your work has quite a lot of errors. I have worked through some of them for you but I have run out of time and don't think I ought to do all your homework for you, so the standard devaition calculation still needs correction. You should also check manually that the various calculations are in fact correct. I trust you will learn from this rather than blindly copy it.
Here is a script to calculate the standard devaition:Code:<html> <script type="text/javascript"> function divide_string() { var data=prompt("Enter your data (separate with a space)",""); data = data.replace(/[^\d\s]/g,"") // strip nonnumeric data = data.replace(/\s+/g, " "); //strip double spaces new_array = data.split(" "); // spliting the new array new_array = new_array.sort(function(a,b){return a  b}) var len= new_array.length; //length of array or number of elements var halfLen = len/2; // half length of the number of elements var med = Math.floor(halfLen);// find the median if(med == halfLen) { median = (new_array[med+1]  new_array[med])/2; } else { median = new_array[med]; } var max=new_array[len1]; var min=new_array[0]; var sum = 0; var stddevn = 0; for (i=0; i<len; i++) { sum = sum + (parseFloat(new_array[i])); // sum } var a= "";// each data squared then the sum of it var b= (sum*sum)/len; // part two of stddevn ( means sum of the data squared divided by number of elements var mean = (sum/len); // mean stddevn = Math.sqrt((ab)/(len1)); // standard deviation alert ("Array: "+new_array+", The mean is: " + mean + " The standard deviation is: " + stddevn+ " The median is: " + median + " The maximum is: " + max +" The min is: " + min) } </script> <FORM> <INPUT TYPE="button" onClick="divide_string()" value="Click here to enter your data"> </FORM> </html>
Sign on a Maine shop: Our motto is to give our customers the lowest possible prices and workmanship.Code:<script type = "text/javascript"> var data = new Array("73", "58", "67", "93", "33", "18", "147"); var deviation = new Array(); var sum = 0; var devnsum = 0; var stddevn = 0; var len = data.length; for (var i=0; i<len; i++) { sum = sum + (data[i] * 1) // ensure number } var mean = (sum/len).toFixed(6); // 6 decimal places for (i=0; i<len; i++) { deviation[i] = data[i]  mean; deviation[i] = deviation[i] * deviation[i]; devnsum = devnsum + deviation[i]; } stddevn = Math.sqrt(devnsum/(len1)).toFixed(6); // 6 decimal places alert ("The mean is: " + mean + " The standard deviation is: " + stddevn) </script>
Last edited by Philip M; 10192008 at 09:08 PM.
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forthfriend (10202008)
10192008, 09:42 PM
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thanks alot
could you tell me why you used a,b and used this function
new_array.sort(function(a,b){return a  b})
thanks for helping me
i realize that some of the equations were wrong but I was able to fix them
thanks once again
Last edited by flouriet; 10202008 at 12:45 PM.
10192008, 11:08 PM
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There is a good explanation at
http://www.javascriptkit.com/javatutors/arraysort.shtml
10202008, 12:54 AM
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somehow this doesn't work
Last edited by flouriet; 10202008 at 01:52 PM.
10202008, 09:05 AM
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Sorry, I can't take over the role of your teacher.
"I have answered three questions, and that is enough,"Code:var a=[1,2,3,4,5,6]; var len=a.length; var med=len/2; if (len%2==0) median=(a[med]+a[med1])/2; else median=a[Math.floor(med)]; alert(median); // RESULT 3.5
Said his father. "Don't give yourself airs!
Do you think I can listen all day to such stuff?
Be off, or I'll kick you down stairs."
 Lewis Carroll
10202008, 09:43 AM
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i really appreciate your help but when i did the first part i got the same answer as you but when i put it into my code and typed in teh same series of numbers it gave me the median of 22.5
10202008, 12:50 PM
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Use alerts after each line to check the progress of the calculation. And be careful to ensure that your variables are numbers, not strings.
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flouriet (10202008)
10202008, 01:59 PM
#11
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thanks for all of your help
I didn't realize you're from London oh I was there about a year ago and love London.