Agallup daily tracking survey found that the mean daily discretionary spending by americans earning over $90,000 per year was $136 per day (usa today, july 30, 2012). the discretionary spending excluded home purchases, vehicle purchases, and regular monthly bills. let x 5 the discretionary spending per day and assume that a uniform probability density function applies with f (x) 5 .00625 for a # x # b. a. find the values of a and b for the probability density function. b. w hat is the probability that consumers in this group have daily discretionary spending between $100 and $200? c. w hat is the probability that consumers in this group have daily discretionary spending of $150 or more? d. w hat is the probability that consumers in this group have daily discretionary spending of $80 or less