Glaucoma is a leading cause of blindness in the United States. Dr. N. Ehlers measured the corneal thickness of eight patients who had glaucoma to test whether or not the average mean thickness would be the same this year as last. Last year the mean corneal thickness was 450. A Minitab printout on the corneal thickness in microns can be found below. Variable N Mean SE Mean StDev C1 8 455.000 9.791 27.692 At the 5% significance level, is there sufficient evidence to conclude that the mean corneal thickness is greater this year than last year? The p-value = 0.3126.