Final answer:
To calculate the expected average winnings per raffle for Roberto, details about the raffle's prize structure and odds are necessary to apply the expected value formula.
Step-by-step explanation:
To determine the expected average winnings per raffle for Roberto if he repeatedly purchases four tickets, we need additional information about the prize structure of the raffle, the number of tickets sold, and the cost of each ticket. In the context of probability, the expected value is calculated by multiplying each outcome by the probability of that outcome and then summing those products. In a raffle, if the chances of winning and the potential winnings are known for purchasing a certain number of tickets, Roberto's expected average winnings could be calculated accordingly.
However, without specific details about the raffle's payouts and odds, it is impossible to provide an exact answer in 200 words. To assist you better, more context on the raffle's structure is needed. If given the prize amounts and the probability of winning, one could determine Roberto's expected winnings by applying the formula for expected value.