For a sample size of 27 we find a mean of 16.3 and a standard deviation of 3.4. What are the endpoints of a 97% confidence interval? Solution n = 27 u = 16.3 s = 3.4 t = 2.295815 (u-t*S/(sqrt(n)),u+t*S/(sqrt(n))) (14.79777867, 17.80222133) 3 Significant Figures, (14.8, 17.8) We are 97% sure that (mean value) is between 14.798 and 17.802..