The graph of which function is decreasing over the interval (–4, ∞)? f(x) = (x + 4)2 + 4 f(x) = –(x + 4)2 + 4 f(x) = (x – 4)2 – 4 f(x) = –(x – 4)2 – 4

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?