probability statistics

Question

In a country, it is known that about 14% of senior citizens (65 years old or older)

get flu each year. However, about 24% of the people under 65 years old get flu

each year. In the general population, there are 12.5% senior citizens.

2.1 What is the probability that a person selected at random from the general

population is a senior citizen a country, it is known that about 14% of senior citizens (65 years old or older)

get flu each year. However, about 24% of the people under 65 years old get flu

each year. In the general population, there are 12.5% senior citizens.

2.1 What is the probability that a person selected at random from the general

population is a senior citizen wn a country, it is known that about 14% of senior citizens (65 years old or older)

get flu each year. However, about 24% of the people under 65 years old get flu

each year. In the general population, there are 12.5% senior citizens.

2.1 What is the probability that a person selected at random from the general

population is a senior citizen who will get the flu this year? (2)

2.2 What is the probability that a person selected at random from the general

population is a person under the age of 65 years who will not get flu this

year? (2)

2.3 What is the probability that a person selected at random from the general

population will get flu this year? (2)

2.4 Given that a person has flu, what is the probability that the person is not a

senior citizen?ho will get the flu this year? (2)

2.2 What is the probability that a person selected at random from the general

population is a person under the age of 65 years who will not get flu this

year? (2)

2.3 What is the probability that a person selected at random from the general

population will get flu this year? (2)

2.4 Given that a person has flu, what is the probability that the person is not a

senior citizen?n who will get the flu this year? (2)

2.2 What is the probability that a person selected at random from the general

population is a person under the age of 65 years who will not get flu this

year? (2)

2.3 What is the probability that a person selected at random from the general

population will get flu this year? (2)

2.4 Given that a person has flu, what is the probability that the person is not a

senior citizen?

Answer 1

2.1

14% * 12.5% = 0.0175 = 1.75%

Likelihood of getting the flu times the percent of senior citizens getting the flu = estimated percent of senior citizens getting the flu.

2.2

(1 - 14%) * (1 - 12.5%)

2.3

Probability of a non-senior getting the flu =

24% * (1 - 12.5%).

Add this to the result in 2.1, since they are independent. (You can't be over 65 and under 65 at the same time.) The sum is the answer.

2.4 P(A|B) = P(A∩B) / P(B)