Practice #8
Solutions
EOQ
BUAD311 – Operations Management
Fall 2009
Hiroshi Ochiumi
1) This is a probability mass function. Fill in the blank
Probability
0.2
0.1
0.15
0.17
0.3
0.08
Value
1
2
3
4
5
6
2) Compute the expected value of random variable X
X
10
11
12
13
14
15
Probability
0.1
0.1
0.1
0.2
0.3
0.2
10*0.1 + 11*0.1 + … + 15*0.2 = 13.1
3) Random variable X is normally distributed with mean 0 and standard deviation 1.
Compute the following probabilities.
a.
Pr(X<0)
0.5
b.
Pr(X<0.52)
0.6985
c.
Pr(X<1)
0.8413
4) Random variable X is normally distributed with mean 10 and standard deviation 2.
Compute the following probabilities.
a.
Pr(X<10)
0.5
b.
Pr(X<11.04)
0.6985
c.
Pr(X<12)
0.8413
5) Random variables X and Y are both normally distributed with mean 100 and standard
deviation 4. It is known that random variable X+Y is also a normal distribution.
a.
What is the mean of X+Y?
200
b.
What is the standard deviation of X+Y?
66
.
5
4
2
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 '07
 Vaitsos
 Management, Standard Deviation, Probability theory, following EOQ problem, Hiroshi Ochiumi

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