# Help Calculating Skewed Deviation Skewness

• Sep 25th 2008, 02:16 PM
cmf0106
Help Calculating Skewed Deviation Skewness
http://img.photobucket.com/albums/v1...orww/help1.jpg
You may recall the formula for calculating skewed deviation skewness http://img.photobucket.com/albums/v1...orww/help2.jpg

[OPTIONAL READING]ill get the sum of the deviation^3 and divide through by ns^3. So the sum of the deviations cubed is 5,286,216,555
divide through by NS in this case 6 * 4263.17^3 = 4.648889288 e 11
5,286,216,555/ 4.648889288 e 11 = cubed skewness of 6.826398755 e 19 which is unfortunately the same incorrect answer I arrived at before.

[PROBLEM] Just to clarify here 5,286,216,555/6 * 4263.17^3 is all that needs to be solved for however 6.826398755 e 19 is not the correct answer and that's what my ti-83 keeps on giving me.

Your ns^3 is incorrect. Make sure you do s^3 first then multiply that by n (6); if in Excel it is easy to screw this up. I worked it through and got a very reasonable answer.

Good luck,

Could some one please tell me what the correct answer is, and what I did wrong so I can correctly solve it? Thanks!
• Sep 25th 2008, 03:35 PM
cmf0106
Just to clarify here 5,286,216,555/6 * 4263.17^3 is all that needs to be solved for however 6.826398755 e 19 is not the correct answer and that's what my ti-83 keeps on giving me.
• Sep 25th 2008, 04:13 PM
mr fantastic
Quote:

Originally Posted by cmf0106
Just to clarify here 5,286,216,555/6 * 4263.17^3 is all that needs to be solved for however 6.826398755 e 19 is not the correct answer and that's what my ti-83 keeps on giving me.

Just to save the wheel being re-invented, the following is an excerpt of an exchange of pm's between myself and the OP:

Quote:

Originally Posted by cmf0106
5,286,216,555 / 6 * 4263.17^3

Everything up to this point is correct so all that needs to be solved is the above, thus some how everytime I am doing it wrong at this step.

6.826398755 e 19 is incorrect that’s what I get when I attempt it

Is it meant to be

5,286,216,555 / (6 * 4263.17^3)

or

(5,286,216,555 / 6) * 4263.17^3?

Your calculator will treat 5,286,216,555 / 6 * 4263.17^3 as the latter, not the former.

Use brackets when using your calculator.

Quote:

meant to be http://img.photobucket.com/albums/v1...orww/help2.jpg
So im guessing the parenthesis are not needed, im just using a ti-83 and put it in as "5,286,216,555 / 6 * 4263.17^3" :(.
Either everyting up to that point is NOT correct, or you're making a data entry error with your calculator.

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Is s = 4263.17? If so, you need the brackets like I said.
• Sep 25th 2008, 04:44 PM
cmf0106
Should I just put the brackets at the beginning and end at the expression then? IE [5,286,216,555 / 6 * 4263.17^3 ]
• Sep 25th 2008, 09:40 PM
mr fantastic
Quote:

Originally Posted by cmf0106
Should I just put the brackets at the beginning and end at the expression then? IE [5,286,216,555 / 6 * 4263.17^3 ]

*Ahem*
Quote:

Originally Posted by mr fantastic
Just to save the wheel being re-invented, the following is an excerpt of an exchange of pm's between myself and the OP:

Is it meant to be

5,286,216,555 / (6 * 4263.17^3)

or

(5,286,216,555 / 6) * 4263.17^3?

Your calculator will treat 5,286,216,555 / 6 * 4263.17^3 as the latter, not the former.

[snip]

Is s = 4263.17? If so, you need the brackets like I said.

Read the red. Do the red.