How much do students pay, on an average, for textbooks during the first semester of college? From a random sample of 250 students from the Corvinus University of Budapest, Hungary, the mean cost was found to be 361.75 Hungarian Forint (Ft), and the sample standard deviation was 37.54 Ft. Assuming that the population is normally distributed, find the margin of error of a 90% confidence interval for the population mean.