Page 83 - Mathematics Class - X

ACTIVITY 7.2

OBJECTIVE
To determine experimental probability of a head (or a tail) by tossing a coin 1000 times and compare it with its
theoretical probability.

MATERIALS REQUIRED

A fair coin Pen Sheets of white paper

PRE-REQUISITE KNOWLEDGE
1. Outcomes of an experiment

2. Knowledge of favourable outcome
3. Concept of probability

THEORY
Number of favourable outcomes
1. Probability of getting a head or a tail on tossing a coin =
Totalnumber of outcomes

2. On tossing a coin, there are two possible outcome, i.e. head and tail, so total number of outcomes is 2. On
tossing a coin, the chance of coming head or tail is 1, i.e. the number of favourable outcomes for head or tail
is 1 because either head will come or tail.

1
∴ Probability of getting a head or a tail on tossing a coin =
2

PROCEDURE
1. Divide the students of the class in 10 groups I, II, III, ..., X.

2. Now each group will toss a coin 100 times and will observe the occurrence of a head.

3. Count the total number of times (frequency) a head comes up in each group and denote these by a , a , ...,
2
1
a , respectively.
10
a a a
4. Calculate the experimental probability of a head in each group as 1 , 2 , ...., 10 .
100 100 100
5. Calculate the experimental probabilities of a head based on the data of 1st group, 1st two groups, ..., all ten

a a + a a + a + a a + a + .... a+
groups as 1 , 1 2 , 1 2 3 ,....., 1 2 10 , respectively.
100 200 300 1000
a a + a a + a + a a + a + .... a+ 1
6. The probabilities 1 , 1 2 , 1 2 3 ,....., 1 2 10 , are coming closer and closer to .
100 200 300 1000 2

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