Find the critical value t for the following situations. a) a 90% confidence interval based on df = 15 b) a 99% confidence interval based on df = 68. T-table Click the icon to view the t-table. Two-tail probability 0.20 0.10 0.05 0.02 0.01 One-tail probability 0.10 0.05 0.025 0.01 0.005 a) What is the critical value of t for a 90% confidence interval with df = 15? Table T If Values of to 3.078 6314 12.706 31.821 63.657 (Round to two decimal places as needed.) 1.886 2.920 4.303 6.965 9.925 1.638 2.353 3.182 4.541 5.841 b) What is the critical value of t for a 99% confidence interval with df = 68? 1.53 2.132 2.776 3.747 1.604 1.476 2.015 2.57 3.365 4.032 (Round to two decimal places as needed.) 1.440 1.943 2.447 3.143 3.707 1.415 1.895 2.365 2.998 3.499 1.397 1.860 2.306 2.896 3.355 0 1.383 1.833 2.26 2.821 3.250 Two tails 10 1.372 1.817 2.228 2.764 3.169 10 11 1.363 1.796 2.201 2.718 3.106 12 1.356 1.782 2.179 2.681 3.055 13 1.350 1.77 2.160 2.650 3.012 13 14 1.34 1.761 2.145 2.624 2.977 14 0 15 1.341 1.753 2.131 2.602 2.947 15 One tail 16 1.337 1.746 2.120 2.583 2.921 16 17 1.333 1.740 2.110 2.567 2.898 17 18 1.330 1.734 2.101 2.552 2.878 18 19 1.328 1.729 2.093 2.539 2.861 19 20 1.325 1.725 2.086 2.528 2.845 20 21 1.323 1.721 2.080 2.518 2.831 21 22 1.321 1.717 2.074 2.508 2.819 22 1.319 1.714 2.069 2.500 2.807 23 24 1.318 1.711 2.064 2.492 2.797 24 25 1.316 1.708 2.060 2.485 2.787 25 1.315 1.706 2.056 2.479 2.779 26 1.314 1.703 2.052 2.473 2.771 27 1.313 1.701 2.048 2.467 2.763 28 1.311 1.699 2.04 2.462 2.756 29 30 1.310 1.697 2.042 2.457 2.750 30 1.309 1.694 2.037 2.449 2.738 32 1.306 1.690 2.030 2.438 2.725 35 1.303 1.684 2.021 2.423 2.704 45 1.301 .679 2.014 2.412 2.690 45 50 1.299 1.676 2.009 2.403 2.678 50 1.296 1.671 2.000 2.390 2.660 60 75 1.293 1.665 1.992 2.377 2.643 75 100 1.290 1.660 1.984 2.364 2.626 100 120 1.289 1.658 1.980 2.358 2.617 120 140 1.288 1.656 1.97 2.35 2.611 140