Statistics and Data Processing (CENP4116)
Computer Engineering - CEN
Semester: First Semester
Level: 400
Year: 2016
COLTECH, First Semester Examination. Course Title: Statistics and Data Processing
Class: AH Level 3. Date: March 17, 2016, Duration: 3Hours. Time: 8:00-11:00
Lecturer: Dr. Nukenine Siri Konje
Question 1(10 points)
a.
Define the following: (i) A Random Variable (ii) A Discrete Random Variable, (iii) A Continuous
Random Variable
b.
1cm length copper wires are manufactured by a certain process. The number of flaws in each
copper wire manufactured varies from wire to wire. Overall, 48% of the wires produced have no
flaws, 39% have one flaw, 12% have two flaws, and 1% has 3 flaws. Let X be the number of flaws
in a randomly selected piece of wire. Find the mean, variance and standard deviation for the
random variable X.
Question 2(15points)
a.
What is a Bernoulli trial? What is the relationship between a Bernoulli trial and a Binomial
distribution? Give an example of a Binomially Distributed trial.
b.
Of 50 buildings in an industrial park, 12have electrical code violations. If 10 buildings are selected
at random for inspection. Assuming that X representing the number of sampled buildings that have
code violations hyper geometrically distributed. What is the probability that exactly 3 of the 10
have code violations? Find the mean and variance of X.
Hint p(x) = P(X=x) =
−
−
/
0 otherwise
=
=
1 −
−
− 1
Question 3(10 points)
a.
The sample mean and standard deviation of the filled-weight of 100 boxes are 12.05 and 0.1
respectively. Find a 95 percent and 99.7 percent confidence interval for the mean filled weight of
all the boxes.
b.
Compute the correlation coefficient of y with respect to x of the data given in the following table.
Interpret your correlation coefficient.
X
53 43 73 66 103 83 93
y 4 6
8
10 12 14 16
Success Wishes
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