In: Statistics and Probability
The budgeting process for a
midwestern college resulted in expense forecasts for the coming
year (in $ millions) of $9, $10, $11, $12, and $13. Because the
actual expenses are unknown, the following respective probabilities
are assigned: 0.27, 0.15, 0.23, 0.16, and 0.19. Show the probability distribution for the expense forecast.
What is the expected value of the expense forecast for the
coming year (to 2 decimals)? What is the variance of the expense forecast for the coming year
(to 2 decimals)? If income projections for the year are estimated at $12 million, how much profit does the college expect to make (report your answer in millions of dollars, to 2 decimals)? |
(a) probability distribution of the expense forecast
x f(x)
9 0.27
10 0.15
11 0.23
12 0.16
13 0.19
(b)
Expected value E(x) is given by:
x f xf x2 f
9 0.27 2.43 21.87
10 0.15 1.5 15
11 0.23 2,53 27.83
12 0.16 1.92 23.04
13 0.19 2.47 32.11
------------------------------- -------------
Total 10.85 119.85
So,
E(x) =
(c)
E(x2) =
Variance = E(x2 ) - (E(x))2 = 119.85 - 10.852 = 2.1275
(d)
Total expense forecast = 9 + 10 + 11 + 12 + 13 = 55
So,
Expected profit = 55 X 0.16 = 8.80