Data from the Bureau of Labor Statistics' Consumer Expenditure Survey show that annual expenditures for cellular phone services per consumer unit increased from $210 in 2001 to $608 in 2007. Let the standard deviation of annual cellular expenditure be $48 in 2001 and $132 in 2007.[You may find it useful to reference thez table.]

a.What is the probability that the average annualexpenditure of 100 cellular customers in 2001 exceeded $200?(Round "z" value to 2 decimal places, and final answer to 4 decimal places.)

b.What is the probability that the average annualexpenditure of 100 cellular customers in 2007 exceeded $600?(Round "z" value to 2 decimal places, and final answer to 4 decimal places.)