(a)
To determine: The probability model for the number of children such couples may have.
The probability model for the number of children is:
X | 1 | 2 | 3 |
P(X=x) | 0.5 | 0.25 | 0.25 |
Given information:
Boys and girls are equally likely.
Formula used:
Here, E is the favourable outcomes and S is the total possible outcomes.
Calculation:
Boys and girls are equally likely:
You have one chance in two that the first born is a girl, thus the probability that X = 1 is,
If the family has 2 children, then the first child was a boy and the second child was a girl, thus multiply the corresponding probabilities:
Since the total probability has to be equal to 1, Then find
Let us combine the found probabilities in a table:
X | 1 | 2 | 3 |
P(X=x) | 0.5 | 0.25 | 0.25 |
(b)
To determine: The expected number of children for the couples.
The expected number of children for the couples.is1.75
Given information:
Boys and girls are equally likely.
Formula used:
Here, E is the favourable outcomes and S is the total possible outcomes.
Calculation:
Boys and girls are equally likely:
You have one chance in two that the first born is a girl, thus the probability that X = 1 is,
If the family has 2 children, then the first child was a boy and the second child was a girl, thus multiply the corresponding probabilities:
Since the total probability has to be equal to 1, Then find
Let us combine the found probabilities in a table:
X | 1 | 2 | 3 |
P(X=x) | 0.5 | 0.25 | 0.25 |
The expected amount is the sum of the product of the possibilities and its probabilities:
Hence, the expected number of children for the couples.is1.75
Chapter 10 Solutions
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