If x1, x2 , , xn are independent rvs, each with the same mean value m and variance s2 , then we have seen that e(x1 + x2 + + xn) ¼ nm and v(x1 + x2 + + xn) ¼ ns2 . in some applications, the number of xi’s under consideration is not a fixed number n but instead a rv n. for example, let n be the number of components of a certain type brought into a repair shop on a particular day and let xi represent the repair time for the ith component. then the total repair time is sn ¼ x1 + x2 + + xn, the sum of a random number of rvs. a. suppose that n is independent of the xi’s. obtain an expression for e(sn) in terms of m and e(n). hint: [refer back to the theorem involving the conditional mean and variance in section 5.3, and let y ¼ sn

you have orange juice on wednesday. (idk why this is the answer)

step-by-step explanation:

answer: on graphs, the open and closed circles, or vertical asymptotes drawn as dashed lines us identify discontinuities.

as before, graphs and tables allow us to estimate at best.

when working with formulas, getting zero in the denominator indicates a point of discontinuity.

when working with piecewise-defined functions, check for discontinuities at the transition points where one piece ends and the next begins.

step-by-step explanation:

if gloria has "carry over" minutes, (that is, any minutes paid for but not used in a month can be applied to her payment for minutes in the next month,) her total usage for the three months is: total minutes = 320 + 243 + 489 = 1052 minutes number of 200 minute blocks = 1052/200 = 5 r52 (that is 5 with a remainder of 52) rounding up the number of 200 minute blocks gives her usage for the three months as 6 blocks. the cost for six blocks is 6 x $25 = $150 she also has 200 - 52 or 148 carry over minutes if gloria pays each month and unused minutes are lost, applying the rounding up procedure to each month gives: first month usage of 320 minutes rounds up to 2 blocks of 200 minutes for a payment of 2 x $25 = $50 second month usage of 243 minutes rounds up to 2 blocks of 200 minutes for a payment of 2 x $25 = $50 third month usage of 489 minutes rounds up to 3 blocks of 200 minutes for a payment of 3 x $25 = $75 total payments for the three months are $50 + $50 + $75 = $175 get the plan with carry over minutes!