Class 7 Maths Chapter 3 Data Handling Exercise 3.4 pdf notes:-
Exercise 3.4 Class 7 maths Chapter 3 Pdf Notes:-
Ncert Solution for Class 7 Maths Chapter 3 Data Handling Exercise 3.4 Tips:-
CHANCE AND PROBABILITY
These words often come up in our daily life. We often say, “there is no chance of it
raining today” and also say things like “it is quite probable that India will win the
World Cup.” Let us try and understand these terms a bit more. Consider the
(i) The Sun coming up from the West (ii) An ant growing to 3 m height.
(iii) If you take a cube of larger volume its side will also be larger.
(iv) If you take a circle with larger area then it’s radius will also be larger.
(v) India winning the next test series.
If we look at the statements given above you would say that the Sun coming up from
the West is impossible, an ant growing to 3 m is also not possible. On the other hand if
the circle is of a larger area it is certain that it will have a largerradius. You can say the same
about the larger volume of the cube and the larger side. On the other hand India can win
the next test series or lose it. Both are possible.
If you toss a coin, can you always correctly predict what you will get? Try tossing
a coin and predicting the outcome each time.
What is probability?
We know that when a coin is thrown, it has two possible outcomes, Head or Tail and for
a die we have 6 possible outcomes. We also know from experience that for a coin, Head
or Tail is equally likely to be obtained. We say that the probability of getting Head or Tail
is equal and is
2 for each.
For a die, possibility of getting either of 1, 2, 3, 4, 5 or 6 is equal. That is for a die
there are 6 equally likely possible outcomes. We say each of 1, 2, 3, 4, 5, 6 has
6 ) probability. We will learn about this in the later classes. But from what we
have done, it may perhaps be obvious that events that have many possibilities can
have probability between 0 and 1. Those which have no chance of happening have
probability 0 and those that are bound to happen have probability 1.
Given any situation we need to understand the different possible outcomes
and study the possible chances for each outcome. It may be possible that the
outcomes may not have equal chance of occuring unlike the cases of the coin and
die. For example, if a container has 15 red balls and 9 white balls and if a ball is
pulled out without seeing, the chances of getting a red ball are much more. Can
you see why? How many times are the chances of getting a red ball than getting
a white ball, probabilities for both being between 0 and 1.