Answer:
$3,762.98
Step-by-step explanation:
Let's compute first the expectancy E (the expected value) of the investment:
E = 30% of 21,000 + 45% of 24,000 + 25% of 30,000 =
0.3*21,000 + 0.45*24,000 + 0.25*30,000 = $24,600
The standard deviation s is
[tex] \bf s=\sqrt{\frac{(E-21,000)^2+(E-24,000)^2+(E-30,000)^2}{3}}[/tex]
When replacing the expectancy in this formula, we get:
[tex] \bf s=\sqrt{\frac{(24,600-21,000)^2+(24,600-24,000)^2+(24,600-30,000)^2}{3}}=\\=3,762.978\approx \$3,762.98[/tex]
