MCQs of Probability

Probability MCQs

Showing 11 to 20 out of 73 Questions

11.

A company has three plants at which it produces a certain item. 30% are produced at plant A, 50% at plant B and remaining at plant C. Suppose that 1%, 4% and 3% of the items produced at plants A, B, C respectively are defective. If an item is selected at random from all those produced, what is the probability that the item was produced at plant B and is defective ?

(a)	0.5
(b)	0.2
(c)	0.02
(d)	0.04

12.

The mean and variance of a random variable X having a binomial distribution are 4 and 2 respectively, then P(X = 1) is _____

(a)	$\frac{1}{16}$
(b)	$\frac{1}{8}$
(c)	$\frac{1}{4}$
(d)	$\frac{1}{32}$

13.

It is given that the events A and B are such that P(A) =

\frac{1}{4}

, P(A l B) =

\frac{1}{2}

, P(B l A) =

\frac{2}{3}

. Then P(B) is _____

(a)	$\frac{1}{2}$
(b)	$\frac{1}{6}$
(c)	$\frac{1}{3}$
(d)	$\frac{2}{3}$

14.

If two events A and B are such that P(A') = 0.3, P(B) = 0.5 and P(A ∩ B) = 0.3, then P(B l A ∪ B') is _____

(a)	0.375
(b)	0.32
(c)	0.31
(d)	0.28

15.

If parameter of a binomial distribution are n = 5 and p = 0.30, then the mean is _____ and variance is _____ .

(a)	1.5, 1.5
(b)	1.5, 1.05
(c)	1.5, 1.40
(d)	1.5, 1.15

16.

A company has three plants at which it produces a certain item. 30 % are produced at plant A, 50 % at plant B and 20 % at plant C. Suppose that 1%, 4% and 3% of the items produced at plants A, B and C respectively are defective. If an item is selected at random from all those produced , what is the probability that the item is defective ?

(a)	0.029
(b)	0.29
(c)	0.025
(d)	0.08

17.

The probability that an event A occurs in a single trial of an experiment is 0.4. Three independent trials of the experiment are performed. The probability that A occurs at least once is _____ .

(a)	0.936
(b)	0.784
(c)	0.904
(d)	0.874

18.

If a random variable X can take all non-negative integral values and the probability that X takes the value r is proportional to α^r (0 < α < 1), then P(X = 0) is _____ .

(a)	1 - α
(b)	α
(c)	$\frac{α}{2}$
(d)	α²

19.

The mean and standard deviation of a random variable X are 10 and 5 respectively. Match the following :

A	B
(i) E(X²)	(p) 0
(ii) E(X(X+1))	(q) 135
(iii) $E ((\frac{X - 10}{5}))$	(r) 125
(iv) $E ({(\frac{X - 10}{5})}^{2})$	(s) 1

(a)	(i) : (q), (ii) : (r), (iii) : (p), (iv) : (s)
(b)	(i) : (r), (ii) : (q), (iii) : (s), (iv) : (p)
(c)	(i) : (r), (ii) : (q), (iii) : (p), (iv) : (s)
(d)	(i) : (p), (ii) : (q), (iii) : (r), (iv) : (s)

20.

A circular wheel numbers 1 to 20 on its surface is rolled twice. What is the probability of getting two 13's?

(a)	$\frac{1}{20}$
(b)	$\frac{1}{40}$
(c)	$\frac{1}{400}$
(d)	$\frac{1}{200}$

Showing 11 to 20 out of 73 Questions