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If d is the standard deviation x, y, and z, what is the stan
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Updated on: 02 Oct 2013, 03:28
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If d is the standard deviation x, y, and z, what is the standard deviation of x + 5, y + 5, z + 5 ? A. d B. 3d C. 15d D. d + 5 E. d + 15 OPEN DISCUSSION OF THIS QUESTION IS HERE: ifdisthestandarddeviationxyandzwhatisthestan93979.html
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Originally posted by gmacvik on 07 Oct 2006, 12:52.
Last edited by Bunuel on 02 Oct 2013, 03:28, edited 1 time in total.
Edited the question and added the OA.



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If d is the standard deviation x,y,and z, what is the standard deviation of x+5,y+5,z+5
1) d
2) 3d
3) 15d
4) d+5
5) d+15
mean = x+y+z+15 / 3 = x+y+7/3+5
varinace = (mean  each value )^2
mean increased by 5 and each value increased with same value
thus variance remains as is and thus sd is the same



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Right  adding or subtracting the same number to all numbers in a set does not change the SD. Multiplying or dividing the same number to all numbers in a set does change the SD.
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Answer is A
Few Tips about SD.
1) If you a add a constant to all terms of a set SD remains the same
2) If you multiply all terms by a constant k new SD k times old SD
3) To determine whether SD for set A is greatero kno SD for a set B we need to the actual terms. Any information abt mean median or range or their combination is not sufficient.
4) basically SD is tedency to deviate from mean. More data deviates more is sd and less the data smaller is SD.
HTH
Yogesh



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D)d+5
Pure POE and guess work  so, if not D, then it's A.



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It is A.
Hey Yogesh, that's what the aspirants here need................
Keep rocking.........
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Re: If d is the standard deviation x, y, and z, what is the stan
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02 Oct 2013, 03:30



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Re: If d is the standard deviation x, y, and z, what is the stan
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30 Jul 2018, 14:04
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Re: If d is the standard deviation x, y, and z, what is the stan &nbs
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