Use the table to answer each question. Note: Round z-scores to the nearest hundredth and then find the required A values using the table.
The breaking point of a particular type of rope is normally distributed, with a mean of 310 pounds and a standard deviation of 24 pounds. What is the probability that a piece of this rope chosen at random will have the following breaking points? (Round your answers to three decimal places.)
(a) less than 280 pounds
(b) between 300 and 330 pounds