A market survey shows that 60% of the population used Brand Z computers last year, 5% of the population quit their jobs

population-brand

#1

A market survey shows that 60% of the population used Brand Z computers last year, 5% of the population quit their jobs last year, and 3% of the population used Brand Z computers and then quit their jobs. Are the events of using Brand Z computers and quitting your job independent?
Is a user of Brand Z computers more or less likely to quit a job than a randomly chosen person?

Answer:

The events are independent! According to the first statistic, 60% of the population uses Brand Z computers. Therefore, 60% of everybody who quit their jobs should use Brand Z computers. And indeed, that is what is shown by stating that 3% of the population who quit their jobs (which is 5% of the population) used Brand Z computers. 3/5∗100=60%. So 60% of those that quit their jobs used Brand Z computers, just like expected. The events are independent, and a user of Brand Z computers is no more likely to quit their job than a randomly chosen person.