Another useful formula concerns the expectation of a sum of randorm variables Referring to first principles as we did in establishing 43 obtain the following as an exercise Eg1X+92X+ gX 44 I think it is time for a break things are beginning to get a bit dull So a guy goes in to see his doctor The doctor evaluates the patient and says I have bad news - you have Alzheimer's disease and you have cancer The guy looks back at his doctor and says At least I don't have Alzheimer's Ok let's get back to business The previous discussion leads to a promi- nent expectation EgX which is obtained when we choose gx X EX2 The variance of a discrete random variable X is defined as VarX = EX-EX2 45 Sometimes we use the notation σ for variance or the simpler notation σ when X is understood Whereas EX is a characteristic of the randorm Not something i expected to see in my statistics textbook Meme

found @ 29 likes ON 2019-02-16 05:29:43 BY ME.ME

source: tumblr