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anonymous
 one year ago
The probability distribution of X is given in the table.
What is the variance of the distribution?
anonymous
 one year ago
The probability distribution of X is given in the table. What is the variance of the distribution?

This Question is Closed

rational
 one year ago
Best ResponseYou've already chosen the best response.2start by finding the mean

rational
 one year ago
Best ResponseYou've already chosen the best response.2dw:1432817965592:dw

rational
 one year ago
Best ResponseYou've already chosen the best response.2mean = 1*.4+2*.1+3*.1+4*.4 = 2.5

rational
 one year ago
Best ResponseYou've already chosen the best response.2good, find the deviation from mean for each of the data values

rational
 one year ago
Best ResponseYou've already chosen the best response.2subtract mean from each data value

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0sub. 2.5 to each point?

rational
 one year ago
Best ResponseYou've already chosen the best response.2Yes, work \(\large x_i  2.5\) for each data value

rational
 one year ago
Best ResponseYou've already chosen the best response.2dw:1432818405802:dw

rational
 one year ago
Best ResponseYou've already chosen the best response.2\(\large (x_i2.5)^2\)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.02.25, .25, .25, 2.25?

rational
 one year ago
Best ResponseYou've already chosen the best response.2dw:1432818549729:dw

rational
 one year ago
Best ResponseYou've already chosen the best response.2when you square, the negative sign disappears thats precicely the reason we square here ok

rational
 one year ago
Best ResponseYou've already chosen the best response.2(1.5)^2 = +2.25 it is not 2.25

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ops, crap. I put it in my calculator wrong then. :/

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@rational so what do I do now?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Its okay :) 2.25 fix from negative to positive :)

rational
 one year ago
Best ResponseYou've already chosen the best response.2dw:1432819551531:dw

rational
 one year ago
Best ResponseYou've already chosen the best response.2multiply each of those by the corresponding probabilities, then add them up

rational
 one year ago
Best ResponseYou've already chosen the best response.2dw:1432819635519:dw

rational
 one year ago
Best ResponseYou've already chosen the best response.2Perfect! 1.85 is the variance

rational
 one year ago
Best ResponseYou've already chosen the best response.2we basically used below formula dw:1432819854547:dw
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