<prompt> S.D. is 1.96 the confidence limit is-63.6066.609599  <response>: Ref:Parks 23rd edition pg 849. SD 1 : confidence limit 68 SD 2 : confidence limit 95 SD 3 : confidence limit 99.7 Here , SD is 1.96, between 1and 2 So, confidence limit will be between 68 and 95, but more close to 95. So answer is 95 