random variable

Question

compute the mean, variance and standard deviation of the random variable X having the following distributions:

 

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x                     0          1             2              3                   4                     5

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P(X = x)         1/8        2/8         1/8           2/8               1/8                    1/8

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Answer 1

I used the TI-84 calculator for this.

 

Into L1   I put  0,1,2,3,4,5

Into L2    I put  .125, .25, .125, .25, .125, .125

 

Then Stat / Calc /1   with List : L1   ; FreqList  : L2    Calculate   gives

 

 mean = 2.375  ( 2 3/8)

   σx = 1.576    (standard deviation)

   Median = 2.5

    the variance is 1.576 ^2 =  2.48