CBSE Questions for Class 12 Commerce Applied Mathematics Probability Distribution And Its Mean And Variance Quiz 6 - MCQExams.com

The probability distribution of a random variable $$X$$ is given below
$$X=x$$$$-1.5$$$$-0.5$$$$0.5$$$$1.5$$$$2.5$$
$$P[X=X]$$$$0.05$$$$0.2$$$$0.15$$$$0.25$$$$0.35$$
The variance of $$X$$ is
  • $$1.6$$
  • $$0.24$$
  • $$0.84$$
  • $$0.75$$
The probability function of a binomial distribution is $$P(x) = \binom{6}{x} p^{x} q^{6 - x}, x = 0, 1, 2, ..., 6$$. If $$2P(2) = 3P(3)$$, then $$p =$$ __________.
  • $$\dfrac {1}{3}$$
  • $$\dfrac {1}{4}$$
  • $$\dfrac {1}{2}$$
  • $$\dfrac {1}{5}$$
The probability that an event A occurs in a single trial of an experiment is $$0.3$$. Six independent trials of the experiment are performed. What is the variance of probability distribution of occurrence of event A?
  • $$12.6$$
  • $$0.18$$
  • $$1.26$$
  • $$1.8$$
What is the mean of $$f(x)=3x+2$$ where x is a random variable with probability distribution.
$$X=x$$$$1$$$$2$$$$3$$$$4$$
$$P(X=x)$$$$1_{/6}$$$$1_{/3}$$$$1_{/3}$$$$1_{/6}$$
  • $$\displaystyle\frac{19}{2}$$
  • $$\displaystyle\frac{5}{2}$$
  • $$\displaystyle\frac{15}{2}$$
  • $$\displaystyle\frac{5}{3}$$
A random variable $$X$$ has the probability distribution,
$$X = x$$$$-2$$$$-1$$ $$0$$$$1$$$$2$$$$3$$
$$P (x)$$ $$\dfrac{1}{10}$$$$K$$$$\dfrac{1}{5}$$$$2K$$$$\dfrac{3}{10}$$$$K$$
  • $$\dfrac{2}{10}$$
  • $$\dfrac{1}{10}$$
  • $$\dfrac{3}{10}$$
  • $$\dfrac{7}{10}$$
An experiment is known to be random if the results of the experiment -
  • Cannot be predicted
  • Can be predicted
  • Can be split into further experiments
  • Can be selected at random
Let $$a={ i }^{ { k }_{ 1 } }+{ i }^{ { k }_{ 2 } }+{ i }^{ { k }_{ 3 } }+{ i }^{ { k }_{ 4 } },(i=\sqrt { -1 } )$$ where each $${k}_{n}$$ is randomly chosen from the set $${1,2,3,4}$$. The probability that $$a=0$$, is 
  • $$\frac { 7 }{ 64 } $$
  • $$\frac { 9 }{ 64 } $$
  • $$\frac { 37 }{ 256 } $$
  • $$\frac { 39 }{ 256 } $$
Two cards are drawn successively with replacement from a well shuffled deck of $$52$$ cards. Find the probability distribution of the number of aces.
  • $$\dfrac{1}{169}$$
  • $$\dfrac{1}{221}$$
  • $$\dfrac{1}{265}$$
  • $$\dfrac{4}{663}$$
A box contains $$10$$ items, $$3$$ of which are defective. If $$4$$ are selected at random without replacement, the probability that at least $$2$$ are defective is?
  • $$50\%$$
  • $$33.33\%$$
  • $$67\%$$
  • $$100\%$$
Given two independent events A and B such that $$P\left( A \right) = 0.3,$$ $$P\left( A\cap B \right) = 0.1$$. Find $$P\left( {A \cap B'} \right)$$
  • $$0.1$$
  • $$0.2$$
  • $$0.15$$
  • $$0.3$$
If the variance of a random variable X is $$\sigma^2$$, then the variance of the random variable X-$$5$$ is?
  • $$5\sigma^2$$
  • $$25\sigma^2$$
  • $$\sigma^2$$
  • $$2\sigma^2$$
Consider the word $$W = MISSISSIPPI$$ Number of ways in which the letters of the word W can be arranged if at least one vowel is separated from rest of the vowels
  • $$\dfrac { 8\ !.16\ ! }{ 4\ !.4\ !.2\ ! } $$
  • $$\dfrac { 8\ !.16\ ! }{ 4.4\ !.2\ ! } $$
  • $$\dfrac { 8\ !.16\ !}{ 4\ !.2\ ! } $$
  • $$\dfrac { 8\ ! }{ 4\ !.2\ ! } .\dfrac { 165 }{ 4\ ! } $$
A biased die is tossed and the respective probabilities for various faces to turn up are given below:
Face:$$1$$$$2$$$$3$$$$4$$$$5$$$$6$$
Probability$$0.1$$$$0.24$$$$0.19$$$$0.18$$$$0.15$$$$0.14$$
If an even face has turned up, then probability that it is face $$2$$ or face $$4$$, is
  • $$0.25$$
  • $$0.42$$
  • $$0.75$$
  • $$0.9$$
A special die with number $$1$$, $$-1$$, $$2$$, $$-2$$, $$0$$ and $$3$$ is thrown thrice. The probability that total is $$6$$ is
  • $$\dfrac{1}{{108}}$$
  • $$\dfrac{{25}}{{216}}$$
  • $$\dfrac{5}{{216}}$$
  • $$\dfrac{5}{{108}}$$
A discrete random variable takes
  • only a finite number of values
  • all possible values between certain given limits
  • infinite number of values
  • a finite or countable number of values
A random variable $$X$$ has the following probability distribution. Find the value of $$10k$$.
$$X$$$$-2$$$$-1$$$$0$$$$1$$$$2$$$$3$$
$$P(X)$$ $$0.1$$$$k$$$$0.2$$$$2k$$$$0.3$$$$k$$
  • 1
  • 2
  • 3
  • 4
A random variable $$X$$ has the probability distribution:
$$X$$:12345678
$$p(X)$$:0.20.20.10.10.20.10.10.1
For the events $$E=\left\{ X\quad is\quad a\quad prime\quad number \right\} $$ and $$F=\left\{ X<4 \right\} $$, the $$P(E\cup F)$$ is
  • $$0.50$$
  • $$0.77$$
  • $$0.35$$
  • $$0.80$$
If  $$P ( A ) = 0.8,$$  $$P ( B ) = 0.5$$   and  $$P \left( \dfrac { B } { A } \right) = 0.4$$ then  $$P \left( \dfrac { A } { B } \right) =?$$
  • $$0.32$$
  • $$0.64$$
  • $$0.16$$
  • $$0.25$$
Two cards are drawn successively with replacement from a well-shuffled deck of $$52$$ cards. Let $$X$$ denote the random variable of number of aces obtained in the two drawn cards. Then $$P(X = 1) + P(X = 2)$$ equals
  • $$\dfrac {52}{169}$$
  • $$\dfrac {25}{169}$$
  • $$\dfrac {49}{169}$$
  • $$\dfrac {24}{169}$$
In the following, find the value of k and find mean and variance of X:
$$X=x$$$$-2$$$$-1$$$$0$$$$1$$$$2$$$$3$$
$$P(X=x)$$$$0.1$$k$$0.2$$$$2k$$$$0.3$$k

Find the value of:
1) k
2) E(X)
3) V(X)
  • $$0.1 , 0.8, 2.16$$
  • $$0.8 , 2.16, 2.16$$
  • $$0.1 , 2, 3$$
  • $$2.16, 0.8, 0.1$$
The outcome of each of $$30$$ items was observed; $$10$$ items gave an outcome $$\dfrac{1}{2}$$- d each, $$10$$ items gave outcome $$\dfrac{1}{2}$$ each and the remaining $$10$$ items gave outcome $$\dfrac{1}{2}+$$ d each. If the variance of this outcome data is $$\dfrac{4}{3}$$ then $$|d|$$ equals:-
  • $$2$$
  • $$\dfrac{\sqrt5}{2}$$
  • $$\dfrac{2}{3}$$
  • $$\sqrt2$$
A perfect die is thrown twice. The expected value of the product of the number of point obtained in two thrown is 
  • $$7/2$$
  • $$7$$
  • $$49/2$$
  • $$none of these$$
A random variable $$X$$ has the following probability mass function:
$$X$$$$-2$$$$3$$$$1$$
$$P(X = x)$$$$\dfrac{\lambda}{6}$$$$\dfrac{\lambda}{4}$$$$\dfrac{\lambda}{12}$$
Then the value of $$\lambda$$ is:
  • $$3$$
  • $$1$$
  • $$4$$
  • $$2$$
For the probability distribution given by $$\left.\begin{matrix} X=x_i & 0 \\ P. & \dfrac{25}{36}\end{matrix}\right|$$ $$\begin{matrix} 1 \\ 5 \\ 18\end{matrix}$$ $$\begin{vmatrix} 2 \\ 1 \\ 36\end{vmatrix}$$ the standard deviation $$(\sigma)$$ is?
  • $$\sqrt{\dfrac{1}{3}}$$
  • $$\dfrac{1}{3}\sqrt{\dfrac{5}{2}}$$
  • $$\sqrt{\dfrac{5}{36}}$$
  • None of the above
A coin is rolled n times. If the probability of getting head at least once is greater than $$90\%$$ then the minimum value of n is?
  • $$4$$
  • $$3$$
  • $$5$$
  • $$6$$
A random variable X has following probability distribution.
$$X=x$$$$1$$$$2$$$$3$$$$4$$$$5$$$$6$$
$$P(X=x)$$K$$3K$$$$5K$$$$7K$$$$8K$$K
Then $$P(2\leq x < 5)=$$ _______.
  • $$\dfrac{3}{5}$$
  • $$\dfrac{7}{25}$$
  • $$\dfrac{23}{25}$$
  • $$\dfrac{24}{25}$$
A random variable $$X$$ has the following probability distribution:
$$X$$$$1$$$$2$$$$3$$$$4$$$$5$$
$$P(X)$$$$k^{2}$$$$2k$$$$k$$$$2k$$$$5k^{2}$$
Then $$P(X>2)$$ is equal to
  • $$\dfrac{1}{6}$$
  • $$\dfrac{7}{12}$$
  • $$\dfrac{1}{36}$$
  • $$\dfrac{23}{36}$$
If the c.d.f.(cumulative distribution function) is given by $$F(x)=\dfrac{x-25}{10}$$, then $$P(27\leq x\leq 33)=$$ ________.
  • $$\dfrac{3}{5}$$
  • $$\dfrac{3}{10}$$
  • $$\dfrac{1}{5}$$
  • $$\dfrac{1}{10}$$
A fair die is tossed repeatedly until a 6 is obtained.Let X denote the number  of tosses required.
The probability that X=3 equals 
  • 25/216
  • 25/36
  • 5/36
  • 125.216
For the following probability distribution.
E(X) is equal to:
1802937_a116af5180c54035a1d3d68ed7ae97d2.PNG
  • 0
  • -1
  • -2
  • -1.8
0:0:1


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