EBM = zα/2 ⋅ = 3 ; n = 36 ; σ The confidence level is 95% (CL = 0.95) CL = 0.95 so = 1−CL = 1−0.95 = 0.05 α = 0.025; = zα/2 z.025 α/2 The area to the right of is 0.025 and the area to the left z.025 of is 1− 0.025 = 0.975 z.05 = = 1.96 zα/2 z.025 using invNorm(0.975,0,1) on the TI-83,83+,84+ calculators. EBM=1.96⋅ = 0.98 = 68 0.98 = 67.02 –EBM − +EBM = 68 + 0.98 = 68.98 The 95% confidence interval is (67.02, 68.98). Interpretation
EBM = zα/2 ⋅ σ = 3 ; n = 36 ; The confidence level is 95% (CL = 0.95) CL = 0.95 so α = 1−CL = 1−0.95 = 0.05 α/2 = 0.025; zα/2 = z.025 The area to the right of z.025 is 0.025 and the area to the left of z.05 is 1− 0.025 = 0.975 zα/2 = z.025 = 1.96 using invNorm(0.975,0,1) on the TI-83,83+,84+ calculators. EBM=1.96⋅ = 0.98 –EBM = 68 − 0.98 = 67.02 +EBM = 68 + 0.98 = 68.98 The 95% confidence interval is (67.02, 68.98). Interpretation