Here are the iq test scores of 31 seventh-grade girls in a midwest school district: 114 100 104 89 102 91 114 114 103 105 108 130 120 132 111 128 118 119 86 72 111 103 74 112 107 103 98 96 112 112 93 these 31 girls are an srs of all seventh-grade girls in the school district. suppose that the standard deviation of iq scores in this population is known to be σ = 15. we expect the distribution of iq scores to be close to normal. estimate the mean iq score for all seventh-grade girls in the school district, using a 99% confidence interval.