# Random Variable Probability

Random variable X takes on the values 5, 20, 3, 200

they each take on the probabilities .60, .30, .08, .02 respectively. Use the statistical capacity of your calculator to find the expected value of X rounded to one place of decimal.

I missed this lecture and I'm confused as to what the statistical capacity means. Could someone show me how to do this on a Casio fx-991MS?

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## 1 Answer

Since listing the Casio buttons here (and I don't know what they are) may be too localized for an answer, could I suggest that you understand the calculation first ? Once you do this, you don't need the Casio any more!

The probabilities are : $p_1=0.60, x_1=5; \\p_2=.30, x_2=20;\\ p_3=.08,x_3=3; \\p_4=.02,x_4=200$.

The expectation is $E(X) = \sum p_ix_i = 0.6\times 5+0.3\times 20 + 0.08 \times 3+0.02 \times 200 = ?$

The "statistical capacity" probably referred to some statistical functions on your calculator. But it's the same as finding the sum above!

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Thanks, I didn't know the equation. –  Unknown Oct 12 '12 at 0:27