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Free download in PDF Probability Distribution Objective Type Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(21)
Which of the following statement is not true for an exponential distribution with parameter λ?
[A]
the distribution is completely determined once the value of λ is known
[B]
the area under the curve is equal to one
[C]
the distribution is a two-parameter distribution since the mean and standard deviation are equal
[D]
standard deviation = 1 / λ
Answer: the distribution is a two-parameter distribution since the mean and standard deviation are equal
(22)
Indicate which of the statements below does not correctly apply to normal probability distributions:
[A]
they all have the same mean and standard deviation
[B]
for the standard normal distribution µ = 0 and σ = 1
[C]
they are all unimodal (ie: have a single mode)
[D]
they are all symmetrical
Answer: they all have the same mean and standard deviation
(23)
Which probability distribution is appropriate for a count of events when the events of interest occur randomly, independently of one another and rarely?
[A]
poisson distribution
[B]
normal distribution
[C]
uniform distribution
[D]
exponential distribution
Answer: poisson distribution
(24)
The mean for the exponential distribution equals the mean for the Poisson distribution only when the former distribution has a mean equal to
[A]
1.0
[B]
2.0
[C]
0.5
[D]
the means of the two distributions can never be equal
(25)
In a popular shopping centre, the waiting time for an ABSA ATM machine is found to be uniformly distributed between 1 and 5 minutes. What is the probability of waiting between 2 and 3 minutes to use the ATM?
[A]
0.40
[B]
0.25
[C]
0.50
[D]
None
(26)
What is the area under a conditional Cumulative density function ?
[A]
1
[B]
Infinity
[C]
Changes with CDF
[D]
0
(27)
The expected value of a discrete random variable ‘x’ is given by
[A]
∑ x P(x)
[B]
P(x)
[C]
∑ P(x)
[D]
1
(28)
If ‘X’ is a continuous random variable, then the expected value is given by
[A]
∫ X P(X)
[B]
∑ x P(x)
[C]
P(X)
[D]
No value such as expected value
(29)
Which of the following distributions is suitable to model the length of time that elapses before the first employee passes through the security door of a company?
[A]
uniform
[B]
poisson
[C]
normal
[D]
exponential
(30)
If E(x) = 2 and E(z) = 4, then E(z – x) =
[A]
6
[B]
0
[C]
2
[D]
Insufficient data
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