There is a government-sponsored study of student achievement in large urban school districts. They give a reading test scored from 0 to 500. A score of 252 is a "basic" reading level and a score of 290 is "proficient." Scores for a random sample of 1400 eighth-graders in a city had x = 257 with standard error 1.0.
Give a 99% confidence interval for the mean score of all the city's eighth-graders. (Be careful: the report gives the standard error of x, not the standard deviation s. Round your answers to one decimal place.)