Question types

PROBABILITY question types

307 questions across 5 question groups — pick any mix to generate a Statistics paper with step-by-step answer keys.

307
Questions
5
Question groups
5
Question types
Sample Questions

PROBABILITY questions

One sample from each question group in this chapter. Select any group above to see the full set with answer keys.

Q 1MCQ1 Mark
If $P(A|B) = P(A)$ and $P(B|A) = P(B),$ then what type of events are $A$ and $B ?$
  • Independent events
  • B
    Complementary events
  • C
    Certain events
  • D
    Impossible events

Answer: A.

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Q 2MCQ1 Mark
If $A ∪ A’ = U,$ then what type of events are $A$ and $A’ ?$
  • A
    Independent variables
  • Complementary events
  • C
    Certain events
  • D
    Impossible events

Answer: B.

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Q 3MCQ1 Mark
Which random experiment from the following random experiment has an infinite sample space ?
  • A
    Throwing two dice
  • B
    Selecting two employees from an office.
  • To measure the life of electric bulb
  • D
    Select a card from $52$ cards

Answer: C.

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Q 4MCQ1 Mark
Which of the following statement for probability of elementary events $H$ and $T$ of a random experiment of tossing a balanced coin is not true ?
  • A
    $P(T) = 0.5$
  • B
    $P(H) + P(T) = 1$
  • $P(H T) = 0.5$
  • D
    $P(H) = 0.5$

Answer: C.

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Q 5MCQ1 Mark
What is the other name of the classical definition of probability ?
  • Mathematical definition
  • B
    Axiomatic definition
  • C
    Statistical definition
  • D
    Geometric definition

Answer: A.

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Q 112 Marks Each2 Marks
The events $A_{1}$ and $A_{2}$ of a random experiment are defined as follows. Find the sets showing union event $A_{1} \cup A_{2}$ and intersection event $A_{1} \cap A_{2}$.
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Q 142 Marks Each2 Marks
Write the sample space of the random experiment of finding the number of defective items while testing the quality of $\mathbf{1 0 0 0}$ items produced in a factory.
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Q 152 Marks Each2 Marks
Two events $A$ and $B$ in the sample space of a random experiment are mutually exclusive. If $3 P(A)=4 P(B)=1$ then find $P(A \cup B)$.
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Q 163 Marks Each3 Marks
One number is randomly selected from the first $50$ natural numbers. Find the sets showing the following events.
$(1)$ The number selected is a multiple. of $5$ or $7.$
$(2)$ The number selected is a multiple of both $5$ and $7.$
$(3)$ The number selected is a multiple of 5 but not a multiple of $7.$
$(4)$ The number selected is only a multiple of $7$ out of $5$ and $7.$
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Q 183 Marks Each3 Marks
There are $3$ boys and $2$ girls in a friend-circle. Two persons are randomly selected from this friend-circle one by one with replacement to sing a song. Find the probability that the first person is a boy and the second person is a girl in the two persons selected to sing a song.
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Q 193 Marks Each3 Marks
There are $12$ screws in a box of which $4$ screws are defective. Two screws are randomly selected one by one without replacement from this box. Find the probability that both the screws selected are defective.
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Q 203 Marks Each3 Marks
If $P\left(A^{\prime}\right)=\frac{7}{25}, P(B / A)=\frac{5}{12}$ and $P(A / B)=\frac{1}{2}$ for two events $A$ and $B$ in the sample space of a random experiment then find $P(A \cap B)$ and $P(B)$.
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Q 214 Marks Each4 Marks
The events $A$ and $B$ of a random experiment are as follows $: A=\{1,2,3,4\}, B=\{-1,0,1\}$ If the sample space $U=A \cup B$ then find the sets showing the following events. $(1)\ B^{\prime}\ (2)\  A^{\prime} \cap B\ (3)\  A-B$
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Q 224 Marks Each4 Marks
There are $3$ yellow and $2$ pink flowers in a basket. One flower is randomly selected from this basket. Denote the selection of yellow flower as an event $A$ and the selection of pink flower as the event $B$. Find the sets representing the following events and answer the given questions. $ \text {(1) }U \text { (2) } A \text { (3) } B \text { (4) } A^{\prime} \text { (5) } B^{\prime} \text { (6) } A \cap B\ { (7) }\ A \cup B\ \text { (8) }\ A \cap B^{\prime}\ {(9) }\ A^{\prime} \cap B\ (10)$ State the elementary events of the sample space for this random experiment. $(11)$ Can it be said that the events $A$ and $B$ are mutually exclusive events ? Give reason. $(12)$ Can it be said that the events $A$ and $B$ are exhaustive events ? Give reason.
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Q 234 Marks Each4 Marks
A factory runs in two shifts. The sample data about the quality of items produced in these shifts are shown in the following table :
Image
One item is randomly selected from the production of the factory.
$(1)$ If the item is taken from the production of the first shift then find the probability that it is defective.
$(2)$ If the item is defective then find the probability that it is taken from the production of the first shift.
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Q 244 Marks Each4 Marks
The sample data obtained about marks scored by a large group of candidates appearing for a public examination of $100$ marks are given in the following table.  $\begin{array}{|c|c|c|c|c|c|} \hline \text{Marks} & 20\ \text{or less} & 21-40 & 41-60 & 61-80 & 81-100 \\ \hline \text{No. of Candidates} & 83 & 162 & 496 & 326 & 124 \\ \hline \end{array}$
One candidate is randomly selected from those appearing for the public examination. Find the probability that this candidate has scored : $(1)$ less than $41$ marks $(2)$ More than $60$ marks $(3)$ Marks from $21$ to $80 .$
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Q 254 Marks Each4 Marks
Two cities $A$ and $B$ of different states have rains on $60 \%$ and $75 \%$ days respectively during the monsoon. For the cities $A$ and $B$, find the probability that on a certain monsoon day,
$(1)$ both the cities have rains
$(2)$ at least one city has rains
$(3)$ only one city has rains.
Note : The events of rains on a day in these two cities are independent.
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