An educational psychologist wishes to know the mean number of words a third grader can read per minute. She wants to make an estimate at the 85% level of confidence. For a sample of 457 third graders, the mean words per minute read was 31.8. Assume a population standard deviation of 4.5. Construct the confidence interval for the mean number of words a third grader can read per minute. Round your answers to one decimal place.