Probability Problems

Question

Question #7

A group of people were asked if they had run a red light in the last year. 402 responded "yes", and 290 responded "no".

Find the probability that if a person is chosen at random, they have run a red light in the last year.

  

Give your answer as a fraction or decimal accurate to at least 3 decimal places

Answer 1

A bit of a fallacy in the question. It has not been demonstrated the quality of the link between people admitting to having run red lights and actually having run red lights, so we can't answer any question about running red lights from the information given. This is an important statistical concept dealing with causality.

We CAN make predictions about how a person will react to a question about having run red lights.

To the question, "Find the probability that if a person is chosen at random, they will say 'yes' to the question of if they had run a red light in the last year" we can find the probability using the basic definition:

P(x) = s/n. where s = number of successes. n = number of trials

P(x='yes'). = 402/(402+290). or 0.580925 - rounded that would be .580