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6.5 – Expected value and variance of a function of X

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Mean and Variance of a linear transformation on a random Variable X

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Find E (X) :

​

Find E (X2):

​

Find Var(X) :

Now use Transformation / code

to find Find E (Y)

AND

Find Var(Y)

Note Var is not affected

By + / –

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Please Note : Random Variable X represents the total value X can take

I.e. total value that coin lands heads up.

And When coin lands heads up its value is 10 cents.

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d

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Note: Writing the formula is a must

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Code x into y and make

New Probability Distribution Table

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Code x into y and make

New Probability Distribution Table

​

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Remember Var(X)

MS—- SM

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Understand your question:

we first identify the random variable before calculating probabilities or expectations.

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