a)let x is randomly distributed sale on a given day.
below is probability distribution of daily sales
P(X=0)=P(contact one buyer and no sale)+P(contact two buyer and
no sale on both)=0.25*0.85+0.75*0.85*0.85=0.7544
P(X=75000)=P(contact one buyer and one sale)+P(contact two buyer
and one
sale)=0.25*0.15+0.75*2C10.85*0.15=0.2288
P(X=150000)=P(contact two buyer and two
sale)=0.75*0.15*0.15=0.0169
b)
|
x |
f(x) |
xP(x) |
x2P(x) |
|
0.0000 |
0.7544 |
0.000 |
0.000 |
|
75000.0000 |
0.2288 |
17156.250 |
1286718750.000 |
|
150000.0000 |
0.0169 |
2531.250 |
379687500.000 |
|
|
total |
19687.500 |
1666406250.000 |
|
|
|
|
|
|
|
E(x) =?= |
?xP(x) = |
19687.5000 |
|
|
E(x2) = |
?x2P(x) = |
1666406250.0000 |
|
|
Var(x)=?2 = |
E(x2)-(E(x))2= |
1278808593.7500 |
|
|
std deviation= |
?= ??2 = |
35760.4334 |
expected value of daily sales =19687.50
c)
standard deviation of daily sales =36760.43
