[RESOLVED] Mean And Standard Deviation

I seem to figure out why my code is not for finding mean and st dev because the code i wrote for finding the sum is working and mean = sum/N so im confused i think i might have the wrong formula/code for standard deviation tho..i just found it online.....:down:

Code:

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Private Sub btnDisplayMean_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayMean.Click

        Dim Mean As Integer
        Dim Sum As Integer
        For J = 0 To MyArray.Count - 1
            Sum = Sum + MyArray(J)
            Mean = CInt(Sum / (MyArray.Count - 1))
        Next
        txtDisplayNumbers.Text = CStr(Mean)
    End Sub


    Private Sub btnDisplaySD_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySD.Click
        Dim Mean As Decimal
        Dim Temp As Double
        Dim Temp2 As Double
        Dim StDev As Double

        For J = 0 To MyArray.Count - 1

            Temp2 = MyArray(J) - Mean
            Temp = Temp + Temp2 * Temp2
            StDev = Math.Sqrt(Temp / MyArray.Count - 1)
        Next
        txtDisplayNumbers.Text = CStr(StDev)
    End Sub

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First up, why would you be calculating the mean inside a loop? The mean is just one value, right? So why would you calculate it more than once?

Also, you say one thing:

Quote:

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mean = sum/N

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yet you do something else:

Code:

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Mean = CInt(Sum / (MyArray.Count - 1))

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You're making the same two errors with your std dev as well.

Quote:

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Originally Posted by jmcilhinney

First up, why would you be calculating the mean inside a loop? The mean is just one value, right? So why would you calculate it more than once?

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Oh wow, im an idiot... I'm calculating it in a loop because of my professor(He's CRAZY) wants it that way...
Ok thank you for your help!

Quote:

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Originally Posted by rosleenXOXO

I'm calculating it in a loop because of my professor(He's CRAZY) wants it that way...

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It's possible that he would want the sum calculated in a loop. Then after the loop, calculate the mean from that sum.

Quote:

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Originally Posted by Evil_Giraffe

It's possible that he would want the sum calculated in a loop. Then after the loop, calculate the mean from that sum.

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I changed it to the way you said :) Thanks a bunch!