bagdbmba wrote:
Bunuel wrote:
bagdbmba wrote:
So why we're discarding the option III here?
The question is which of the options must be true?
Consider the example in my post. Does any of the options hold true for it?
Got it!
How I could know that which example set would be best to plug-in for soln? I mean is there any baseline to determine which set would be ideal to consider?
Details:
Q= {2,3,4}
Standard deviation :
1. mean = 3
2. difference: 1,0,-1
3. squaring: 1,0,1
4. mean again = (1+0+1)/3 = 2/3
5. root over (2/3) = standard deviation.
Now, Adding the man to the set Q . So {2,3,3,4}
same way standard deviation: root over (1/2)
Certainly standard deviation decreases after adding mean 3.
The mean was M=3 and added number N=3 too and first standard deviation D= root over (2/3)
So N=M ( I and II both eliminated}
we can see, N>D . So III eliminated. Nothing is must be true here...............
The example here {1,2,3} works well too, we can use it here conveniently....
start something like {1,2,3} or {2,3,4}...
Basics of this math is, add mean to a set and standard deviation will decrease certainly.........