Table 1: Data for Problem 4, Distribution of astigmatism in 1033 British military recruits, ages 18-22 Degree of astigmatism (diopters) Frequency 0.0 or less than 0.2 458 0.2-0.3 268 0.4-0.5 151 0.6-1.0 79 1.1-2.0 44 2.1-3.0 19 3.1-4.0 9 4.1-5.0 3 5.1-6.0 2 1033