FindMeanAndVariance

# FindMeanAndVariance - a) After finding the mean above,...

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Finding the Mean (Expectation), Variance, and Standard Deviation of a Discrete Probability Distribution Using the STAT Menu of the TI-83/TI-84 Graphing Calculator 1. To find the mean, μ , of the distribution of a discrete random variable X: a) Choose STAT , Edit . b) Enter the list of possible values of X in column L1 . c) Enter the list of probability values, P(X = x), in column L2 . d) Choose 2 nd , Quit to get out of the STAT menu. e) Choose 2 nd , List , L1 , , 2 nd , List , L2 , STO , 2 nd , List , L3 . This multiplies each x by the corresponding P(X = x), and stores the result in column L3 . f) To find the mean, choose STAT , Calc , 1-Var Stats , 2 nd , List , L3 . Hit Enter . g) The value that you see for Σ x is the mean, μ , of the distribution. 2. To find the variance, σ 2 , of the distribution of a discrete random variable X:
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Unformatted text preview: a) After finding the mean above, choose 2 nd , List , L1 , ∧ , 2 , STO , 2 nd , List, L4 . This will square the values of X and store the values in column L4 . b) Choose 2 nd , List , L4, , 2 nd , List , L2 , STO , 2 nd , List , L5 . This multiplies the squared x’s by the corresponding probabilities and stores the results in L5 . c) Choose STAT , Calc , 1-Var Stats , 2 nd , List , L3 . Hit Enter . d) The value that you see for Σ x is the value of ( 29 ∑ = x X P x 2 . e) To get the variance, subtract μ 2 from the number obtained in (d). 3. To find the standard deviation of the distribution, take the square root of the number obtained in part 2, above....
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## This note was uploaded on 07/28/2011 for the course STA 2014 taught by Professor Staff during the Fall '10 term at University of Florida.

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