Two sets of elementary schoolchildren were taught to read by using different methods, 50 by each method. At the conclusion of the instructional period, a reading test yielded the results Y1 = 75, Y2 = 72, 51 = 9, and s2 = 11. (a) What is the attained significance level if you wish to see whether evidence indicates a difference between the two population means? (Round your answer to four decimal places.)