CHE 4253  Quiz 3
Instructor: Dimitrios V. Papavassiliou
October 24, 2006
Name:……………………….
OU ID:………………………
Answer all questions and show your calculations, if any are necessary.
1.
(15 points) If the profit probability density function is shown by the following figure,
what is the Expected Profit for this process?
What it the standard deviation of this probability density function and what is the
coefficient of variation?
Mean value= 2*0.05+(1)*0.1+0*0.2+1*0.25+2*0.2+3*0.1+4*0.05+5*0.05=1.2
Standard deviation= [(21.2)
2
*0.05+(11.2)
2
*0.1+(01.2)
2
*0.2+(11.2)
2
*0.25+(2
1.2)
2
*0.2+(31.2)
2
*0.1+(41.2)
2
*0.05+(51.2)
2
*0.05]
1/2
=
[0.512+0.484+0.288+0.01+0.128+0.324+0.392+0.722]
1/2
=2.86
1/2
= 1.691
Coef. of variation = standard dev/mean value = 1.41
CHE 4253 Quiz3, Page 1 of
3
Probability
0.3
0.2
0.1
2
1
0
1
2
3
4
5
Profit, $10
5
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View Full Document2. (10 points) A company must purchase a reactor to be used in an overall operation. Four
reactors have been designed, all of which are equally capable of giving the required service. The
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 Spring '09
 Lobban
 Variance, Probability theory

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