Final answer:
The probability that someone buys gas OR does not buy a car wash, P(YG U NW), is calculated using the principle of inclusion-exclusion and the values from the contingency table, resulting in 0.940.
Step-by-step explanation:
To calculate the probability that someone buys gas OR does not buy a car wash, denoted as P(YG U NW), we use the contingency table provided. According to the principle of inclusion-exclusion in probability, the probability of the union of two events, A and B, is given by P(A U B) = P(A) + P(B) - P(A and B).
In this scenario, event A is 'buys gas' (YG) and event B is 'does not buy a car wash' (NW). The probabilities from the contingency table are P(YG) = 0.22 + 0.56 = 0.78, P(NW) = 0.56 + 0.16 = 0.72, and P(YG and NW) = 0.56. So, P(YG U NW) = P(YG) + P(NW) - P(YG and NW) = 0.78 + 0.72 - 0.56 = 0.94.
Therefore, the probability that someone buys gas OR does not buy a car wash is 0.940, rounded to three decimal places as requested.