sd2
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- DanaJ
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Mean for x, y, z = m
Mean for x+5, y+5, z+5 = [(x+y+z)+15]/3 = m+5
Because the difference between m+5 and either x+5, y+5 or z+5 is the same as the difference between m and x, y or z (eg. m+5-x-5 = m-x), you will have the same standard deviation.
Mean for x+5, y+5, z+5 = [(x+y+z)+15]/3 = m+5
Because the difference between m+5 and either x+5, y+5 or z+5 is the same as the difference between m and x, y or z (eg. m+5-x-5 = m-x), you will have the same standard deviation.
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SD should be "d" only.
Remember this two rules..
SD(x+c) = SD(x) c--> constant.
SD(x * c) = c*SD(x)
Remember this two rules..
SD(x+c) = SD(x) c--> constant.
SD(x * c) = c*SD(x)
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Thanks for reminding.. i forgot the multiplication rule..amitabhprasad wrote:SD should be "d" only.
Remember this two rules..
SD(x+c) = SD(x) c--> constant.
SD(x * c) = c*SD(x)
- logitech
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Once again SD questions test your knowledge not your calculation skills.
Standard Deviation is the distance from the average
A B C can be 0 0 and 0 and the average is 0 and the SD is 0 because they are all the same numbers
if you add the same number to all of them
5 5 5 well, this time the average will INCREASE with the SAME number you added to each number
So NUMBER - AVERAGE = WILL BE THE SAME
and as a result SD wont change!
Standard Deviation is the distance from the average
A B C can be 0 0 and 0 and the average is 0 and the SD is 0 because they are all the same numbers
if you add the same number to all of them
5 5 5 well, this time the average will INCREASE with the SAME number you added to each number
So NUMBER - AVERAGE = WILL BE THE SAME
and as a result SD wont change!
LGTCH
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