Question 1036954
E(X) = 1,060*0.5 + 1,400* 0.1 + 1,620* 0.4 = 1,318, the expected number of admissions for the fall semester.

{{{E(X^2) = 1060^2*0.5 + 1400^2* 0.1 + 1620^2* 0.4 = 1807560}}}

==> {{{Var(X) = E(X^2) - (E(X))^2 = 1807560 - 1737124 = 70436}}}

=> {{{SD(X) = sqrt(Var(X)) = sqrt(70436) = 265.40}}}, to two decimal places (the zero at the hundredth place is significant.)