Adding, Multiplying and adding independent variables.

In class we reviewed what happens to the expected value E(x) and standard deviation s(x) when we add/subtract a constant and multiply/divide a constant.

add/subtract a constant...E(x ± c) = E(x) ± c
                                        s(x ± c) = s(x)


multiply/divide a constant...E(ax) = a E(x)
                                             s(ax) = a s(x)


Afterwards, we talked about what happens when we add two independent variables.


adding two (or more) independent variables...E(x1 ± x2) = E(x1) ± E(x2)

Notes - Discrete Random Variables (cont.)

HW - pgs. 384-385 (21, 23, 27, 33, 35, 36)
          read pgs. 377-381