To apply a Poisson probability distribution, the mean can be computed as _______ n pi sigma X e^-x mu^xe^-x/x David's gasoline station offers 4 cents off per gallon if the customer pays in cash and does not use a credit card. Past evidence indicates that 40% of all customers pay in cash. During a one-hour period, 15 customers buy gasoline at this station. What is the probability that at least 10 pay in cash? 0.024 0.033 0.009 0.976