Appendix Tables A-9 Table A.5 Critical Values for t Distributions 4, density curve Shaded area - a 0 .10 .05 025 .01 .005 .001 .0005 3.078 6.314 12.706 31.821 63.657 318.31 636.62 1.886 2.920 4.303 6.965 9.925 22.326 31.598 1.638 2.353 3.182 4.541 5.841 Jan AWN 1.533 10.213 12.924 2.132 2.776 3.747 4.604 7.173 8.610 1.476 2.015 2.571 3.365 4.032 5.893 6.869 1.440 1.943 2.447 3.143 3.707 5.208 5.959 1.415 1.895 2.365 2.998 3.499 4.785 5.408 1.397 1.860 2.306 2.896 3.355 4.501 5.041 1.383 1.833 2.262 2.821 3.250 4.297 .781 1.372 1.812 2.228 2.764 3.169 4.144 1.363 4.587 11 1.796 2.201 2.718 3.106 4.025 4.437 1.356 1.782 2.179 2.681 3.055 1.350 3.930 4.318 1.771 2.160 2.650 3.012 1.345 3.852 1.761 2.145 4.221 2.624 2.977 3.787 4.140 1.341 1.753 2.131 2.602 2.947 3.733 1.337 1.746 4.073 2.120 2.583 2.921 3.686 4.015 1.333 1.740 2.1 10 2.567 2.898 3.646 3.965 1.330 1.734 2.101 2.552 2.878 3.610 1.328 3.922 1.729 2.093 2.539 2.861 3.579 3.883 1.325 1.725 2.086 2.528 2.845 3.552 1.323 3.850 1.721 2.080 2.518 2.831 1.321 3.527 1.717 3.819 2.074 2.508 2.819 3.505 1.319 1.714 3.792 2.069 2.500 2.807 3.485 3.767 1.318 1.711 2.064 2.492 2.797 3.467 3.745 1.316 1.708 2.060 2.485 2.787 3.450 3.725 1.315 1.706 2.056 2.479 2.779 3.435 3.707 1.314 1.703 2.052 2.473 2.771 3.421 1.313 3.690 1.701 2.048 2.467 2.763 1.311 3.408 3.674 1.699 2.045 2.462 2.756 3.396 3.659 30 1.310 1.697 2.042 2.457 2.750 32 3.385 1.309 3.646 1.694 2.037 2.449 2.738 3.365 34 1.307 3.622 1.691 2.032 2.441 2.728 3.348 36 3.601 1.306 1.688 2.028 2.434 2.719 3.333 38 3.582 1.304 1.686 2.024 2.429 2.712 3.319 3.566 40 1.303 1.684 2.021 2.423 2.704 3.307 3.551 50 1.299 1.676 2.009 2.403 60 2.678 3.262 1.296 3.496 1.671 2.000 2.390 120 2.660 3.232 1.289 3.460 1.658 1.980 2.358 2.617 3.160 3.373 1.282 1.645 1.960 2.326 2.576 3.090 3.291A-6 Appendix Tables Table A.3 Standard Normal Curve Areas D(2) = P(Z s z) Standard normal density curve Shaded area = (z) 0 Z .00 .01 .02 .03 .04 .05 .06 .07 .08 09 -3.4 0003 0003 0003 .0003 0003 0003 .0003 .0003 0003 0002 -3.3 .0005 .0005 0005 .0004 0004 0004 0004 0004 0004 0003 -3.2 .0007 0007 0006 .0006 0006 .0006 0006 0005 0005 0005 -3.1 .0010 0009 0009 .0009 0008 0008 0008 0008 0007 0007 -3.0 .0013 .0013 .0013 .0012 .0012 .001 1 .0011 .0011 .0010 0010 -2.9 .0019 .0018 0017 .0017 0016 0016 .0015 .0015 .0014 0014 -2.8 .0026 0025 .0024 .0023 .0023 .0022 0021 .0021 .0020 0019 -2.7 0035 .0034 0033 .0032 0031 0030 .0029 0028 .0027 .0026 -2.6 0047 .0045 .0044 .0043 .0041 .0040 0039 .0038 0037 0036 -2.5 .0062 .0060 0059 0057 .0055 0054 0052 0051 0049 0038 -2.4 .0082 .0080 .0078 .0075 .0073 .0071 .0069 .0068 .0066 .0064 -2.3 .0107 .0104 .0102 .0099 .0096 .0094 .0091 .0089 .0087 .0084 -2.2 .0139 .0136 .0132 .0129 .0125 .0122 .01 19 .0116 .0113 .01 10 -2.1 .0179 .0174 .0170 .0166 .0162 .0158 .0154 .0150 .0146 .0143 -2.0 .0228 .0222 .0217 .0212 .0207 .0202 .0197 .0192 .0188 .0183 -1.9 .0287 .0281 .0274 .0268 .0262 .0256 .0250 .0244 .0239 .0233 -1.8 .0359 .0352 .0344 .0336 0329 .0322 .0314 .0307 .0301 0294 -1.7 .0446 .0436 .0427 .0418 .0409 .0401 0392 .0384 .0375 0367 -1.6 .0548 0537 .0526 .0516 0505 0495 .0485 .0475 0465 0455 -1.5 .0668 .0655 .0643 .0630 .0618 .0606 .0594 .0582 .0571 0559 -1.4 0808 0793 0778 0764 0749 0735 0722 0708 .0694 0681 .0968 .0951 .0934 .0918 .0901 .0885 .0869 0853 0838 0823 -1.2 .1151 .1131 .1112 .1093 .1075 1056 .1038 .1020 .1003 0985 -1.1 .1357 .1335 .1314 . 1292 .1271 1251 .1230 .1210 .1 190 .1170 -1.0 .1587 1562 .1539 .1515 .1492 1469 .1446 .1423 .1401 .1379 -0.9 .1841 .1814 .1788 1762 1736 .1711 . 1685 .1660 .1635 1611 -0.8 .21 19 .2090 .2061 .2033 .2005 .1977 . 1949 .1922 .1894 .1867 -0.7 .2420 .2389 .2358 .2327 .2296 .2266 .2236 .2206 .2177 .2148 -0.6 .2743 .2709 .2676 .2643 .2611 .2578 .2546 .2514 .2483 .2451 -0.5 .3085 .3050 .3015 .2981 2946 .2912 .2877 .2843 .2810 .2776 -0.4 3446 .3409 .3372 .3336 3300 .3264 .3228 .3192 .3156 .3121 -0.3 .3821 .3783 .3745 .3707 3669 .3632 .3594 .3557 .3520 .3482 -0.2 4207 4168 4129 4090 4052 4013 .3974 3936 .3897 .3859 -0.1 4602 4562 4522 4483 4443 4404 4364 .4325 4286 4247 -0.0 .5000 .4960 4920 .4880 4840 .4801 .4761 4721 .4681 .4641\fAssume that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true standard deviation 0.78. . Compute a 98% CI for the true average porosity of a certain seam if the average porosity for 25 specimens from the seam was 4.87. 0 Compute a 99% CI for true average porosity of another seam based on 18 specimens with a sample average porosity of 4.58. . How large a sample size is necessary if the width of the 98% in- terval is to be 0.40
