Question

Plans toPlans tovote "yes"vote "no"Totalon issue Qon issue QPlans tovote "yes"81220on issue P.Plans tovote "no" on141630issue PTotal222850The table shows a survey of 50 registered votersin a city. Each voter was asked whether theyplanned to vote “yes” or “no” on two differentissues. If a voter who plans to vote “yes” on issuePis randomly selected, what is the probability thatvoter also plans to vote "no" on issue Q?

Answer 1

Consider that the probability of an event is given by,

`\text{Probability of an event}=\frac{\text{ No. of events favorable to the event}}{\text{ Total possible no. of outcomes}}`

Consider the following events,

A = event that a voter plans to vote 'yes' on issue P

B = event that a voter plans to vote 'no' on issue Q

Then, given that event A has already occurred, the probability of occurrence of B, is given by,

`P((B)/(A))=(P(A\cap B))/(P(A))`