A market research company employs a large number of typists to enter data into a computer database. The time it takes for potential newtypists to learn the computer system is known to have a Normal distribution with a mean of 90 minutes and a standard deviation of 18 minutes. A candidate is automatically hired if she learns the computer system in less than 100 minutes. A cut-off time is set at the slowest 10% of the learning distribution. Anyone slower than this cut-off time is definitely not hired. a. What proportion of candidates takes more than two hours to learn the computer system?
b. What proportion of candidates will be hired automatically?
c. What is the cut-off time the market research company uses?