In: Statistics and Probability
The following two-way contingency table gives the breakdown of the population of adults in a particular locale according to employment type and level of life insurance:
Level of Insurance |
|||
Employment Type |
Low |
Medium |
High |
Unskilled |
0.07 |
0.19 |
0.00 |
Semi-skilled |
0.04 |
0.28 |
0.08 |
Skilled |
0.03 |
0.18 |
0.05 |
Professional |
0.01 |
0.05 |
0.02 |
An adult is selected at random. Find each of the following
probabilities.
a. The person has a high level of life insurance.
b. The person has a high level of life insurance, given that he
does not have a professional position.
c. The person has a high level of life insurance, given that he has
a professional position.
d. Determine whether or not the events “has a high level of life
insurance” and “has a professional position” are independent.
Solution :
Probability of an event E is given by,
a) P(high) = (0.00 + 0.08 + 0.05 + 0.02)
P(high) = 0.15
Hence, the probability that a randomly selected adult has a high level of insurance is 0.15.
b) We have to find P(high | not professional)
Hence, the probability that The person has a high level of life insurance, given that he does not have a professional position is 0.1413.
c) We have to find P(high | professional)
Hence, the probability that The person has a high level of life insurance, given that he has a professional position is 0.25.
d) Two events "“has a high level of life insurance” and “has a professional position" are said to be independent iff,
P(high and professional) = P(high).P(professional)
We have,
P(high and professional) = 0.02
P(high) = 0.15
P(professional) = 0.05
P(high).P(professional) = (0.15 × 0.05) = 0.0075
Hence, the events has a high level of life insurance” and “has a professional position” are not independent.