I. the national assessment of educational progress tested a simple random sample of 1,000 thirteen year old students in both 2004 and 2008 (two separate simple random samples). the average and standard deviation in 2004 were 257 and 39, respectively. in 2008, the average and standard deviation were 260 and 38, respectively. calculate a 90% confidence interval for the change in average scores from 2004 to 2008, and interpret this interval in the context of the application. (reminder: check conditions.)31