ENGTECH 3ST3
– WEEK 5 –
Quiz #2 Example Q&A
Quiz 2 Example Q&A
2
1) A discrete random variable X is any random variable whose possible
values either constitute a finite set or else can be listed in an infinite
sequence. TRUE or FALSE? TRUE
2) Each trial results in at least two outcomes is a condition of a
binomial experiment. TRUE or FALSE? FALSE
3) When analyzing the performance of an engineered system over time,
with failures constituting the events of interest, what is the
appropriate probability distribution to use? POISSON DISTRIBUTION
4) The cumulative distribution function F(x) of a discrete random
variable X is given by F(0) = .20, F(1) = .60, F(2) = .85, and F(3) =
1.0, then the value of the probability mass function p(x) at x = 2 is?
0.25
5) Let X be a discrete random variable with V(X) = 3.4, then V(2X + 7.9)
is? 13.6
Quiz 2 Example Q&A
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6) If the probability density function of a continuous random
variable X is f(x) = kx (0 < x < 2) then the value k is? 1/2
7) What is the measure called if the area under the density curve
to the right is 0.5? MEDIAN
8) If the population distribution of a variable is approximately
normal, what is the middle area under the density curve with a
range of ± 2σ? 95%
9) If X is a normally distributed random variable with a mean of
10 and standard deviation of 5, then the probability that X is
between 5 and 15 is? 68%
10) If X is a normally distributed random variable, then the P(X=x)
at any specified value is? 0.00
Questions Period
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