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May 29, 2015

Posted by **Fakaapo. Suetusi** on Wednesday, April 18, 2012 at 4:42am.

Thank you for your help.

- Please can you help me (Probability) -
**MathMate**, Wednesday, April 18, 2012 at 7:31amSuppose the dataset is:

x(i)=1,3,5,7,9

sum=∑x=25

mean=μ=25/5=5

x(i)^2=1,9,25,49,81

sum of squares=∑x^2=165

Var(x)=(165-5^2)/5=28

If all the numbers in the dataset are multiplied by 2:

x(i)=2,6,10,14,18

sum=∑x=50

mean=μ=50/5=10

x(i)^2=4,36,100,196,324

sum of squares=∑x^2=660

Var(x)=(660-10^2)/5=112 (=4*28)

What can you say about the effect on variance of multiplying the dataset by a constant?