Page 10 - Life Insurance Today March 2016
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the probability of the occurrence of an event of getting b. A queen;
Head on upper side is one out of the two. Here, in this first c. A black card.
case, the probability is 0.5 (i.e. ½) which is equal to (=) the
ratio of: a. Probability in this case is 13 1
Nos. of favourable events that may occur in this case No. of favourable events of getting 13 ==
cards of Heart suit out of total 52 cards
Total number of mutually exclusive & exhaustive events. so there may be 13 ways 14
But in the second case there are likely six outcomes P=
(events) possible on throwing a dice. They are, either face There being 52 cards & any one may
numbered 1 or 2 or 3 or 4 or 5 or 6 may turn up. All these come so 52 nos. equally & mutually
six events are mutually exclusively, i.e. no two of them can exclusive and exhaustive ways
occur simultaneously. Secondly there are only six possible
events i.e. they are exhaustive events. Out of these b. Probability in this case is 41
mutually and exhaustive six events, only one is favourable No. of favourable events of getting 4 = 52 = 13
to face up, say number 2 turning up on top. Thus the cards of Heart suit out of total 52 cards
probability of the event of getting face numbered 2 on top so there may be 4 ways
is one out of six. Here, in the second case, the probability
is 0.166667 i.e. 1/6 which is equal to (=) the ratio of: P = There being 52 cards & any one may
Nos. of favourable events that may occur in this case come so 52 nos. equally & mutually
exclusive and exhaustive ways
Total numbers of mutually exclusive & exhaustive events.
c. Probability in this case is 26 1
C. Mathematical definition of probability: No. of favourable events of getting 26 ==
cards of Heart suit out of total 52 cards
In general,probability has been defined mathematically as so there may be 26 ways 52 2
under:
If an event can happen in M ways out of N equally likely, P=
mutually exclusive and exhaustive ways then the There being 52 cards & any one may
probability that the event will happen when a trail is made come so 52 nos. equally & mutually
is M/N. exclusive and exhaustive ways
Example: Out of a pack of 52 cards, if one card is drawn The mathematical definition of probability has a limited
at random, let us examine what is the probability that the use, as in very limited situations it is possible to decide
card drawn is - total number of equally likely mutually exclusive and
a. A Heart; exhaustive ways out of which some are favourable to a
particular event. So we need to go for more effective
definition of probability.
D. Statistical definition of probability:
If out of 'N' number of trials, an event happens in 'M' trials
then the fraction N/M is called the relative frequency. The
limit of the relative frequency as the number of trials is
increased indefinitely is defined as the probability of
occurrence of an event when a trail is made. The statistical
definition is based on experimentation. It is assumed that
the values of relative frequency 'N/M' do cluster more and
more closely round a limiting value, say 'P', as 'N' becomes
larger and larger.
"I am so clever that sometimes I don't understand a single word of what I am saying."
10 March 2016 Life Insurance Today
