please contruct 90, 95, and 99 percent confidence intervals for the difference between population means
6.4.4 The purpose of a study by Nozawa et al. $(A-10)$ was to determine the effectiveness of segmental wire fixation in athletes with spondylolysis. Between 1993 and 2000,20 athletes ( 6 women and 14 men) with lumbar spondylolysis were treated surgically with the technique. The following table gives the Japanese Orthopaedic Association (JOA) evaluation score for lower back pain syndrome for men and women prior to the surgery. The lower score indicates less pain. Source: Satoshi Norawa, Katsuji Shimins, Kei Miyamoto, and Miruo Tanaka, "Repair of Pars Interarticularis Defect by Segmental Wire Fixation in Young Athletes with Spondylolysis," Americon Journal of Sports Medicine, 3r (2003), 359-364.