Vidaara.orgClass 9 · Mathematics
CodeVID-M09-15-HSM-01
Meaning & Scope of Probability - Assignment
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Section A carries 1 mark each, Section B 2 marks, Section C 3 marks and Section D 5 marks.
- Show all working for Sections B, C and D. Only final answers are given at the end — for full solutions, raise your doubts with your teacher.
Section A — Multiple Choice Questions
5 × 1 = 5 marks
1.
Probability measures the ___ of an event.
- A.cost
- B.likelihood
- C.length
- D.weight
2.
The probability of an event lies between:
- A.$-1$ and $1$
- B.$0$ and $1$
- C.$0$ and $100$
- D.$1$ and $2$
3.
The probability of a certain event is:
- A.$0$
- B.$0.5$
- C.$1$
- D.$2$
4.
The probability of an impossible event is:
- A.$0$
- B.$0.5$
- C.$1$
- D.$-1$
5.
The sum of probabilities of all outcomes is:
- A.$0$
- B.$0.5$
- C.$1$
- D.$2$
Section B — Short Answer (2 marks)
4 × 2 = 8 marks
6.
Between which two values does a probability lie?
7.
What is the probability of a certain event?
8.
What is the probability of an impossible event?
9.
What does probability measure?
Section C — Short Answer (3 marks)
4 × 3 = 12 marks
10.
Can a probability be $1.5$? Why?
11.
Can a probability be negative?
12.
If the probability of rain is $0.7$, what is the probability of no rain?
13.
The probability of an event is $\tfrac{2}{5}$. What is the probability it does not happen?
Section D — Long Answer (5 marks)
2 × 5 = 10 marks
14.
Explain, with the certain and impossible events as examples, why $0\le P(E)\le1$.
15.
If $P(E)=0.35$, find $P(\text{not }E)$ and state what each value means.
Answer Key
Section A — Multiple Choice Questions
- (B) likelihood
- (B) $0$ and $1$
- (C) $1$
- (A) $0$
- (C) $1$
Section B — Short Answer (2 marks)
- $0$ and $1$.
- $1$.
- $0$.
- The likelihood (chance) of an event.
Section C — Short Answer (3 marks)
- No; probability cannot exceed $1$.
- No; it cannot be less than $0$.
- $0.3$.
- $\tfrac{3}{5}$.
Section D — Long Answer (5 marks)
- An impossible event has $P=0$ and a certain event has $P=1$; every other event lies between, so $0\le P(E)\le1$.
- $P(\text{not }E)=0.65$; the event is fairly unlikely, its complement fairly likely.
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