Statistics Homework 9.2

2. Determine the tvalue in each of the cases. 1 Click the icon to view the table of areas under the tdistribution. (a) Find the tvalue such that the area in the right tail is 0.025 with 24 degrees of freedom. (Round to three decimal places as needed.) (1)) Find the tvalue such that the area in the right tail is 0.01 with '15 degrees of freedom. (Round to three decimal places as needed.) (c) Find the t-value such that the area left of the t-value is 0.25 with 5 degrees of freedom. [Hint: Use symmetry.] (Round to three decimal places as needed.) (d) Find the critical t-value that corresponds to 99% condence. Assume 17 degrees of freedom. (Round to three decimal places as needed.) 1: Table 01 t-Distribution Areas 121 A re a in r131\" tail Table VI tlestthntIon Area in Right Tail 0! 0.15 0.20 0.15 0.10 0.05 0.075 0.02 0.01 0.005 0.0015 0.001 0.0005 1 1.000 1.376 1.963 3.078 6.314 12.706 15.894 31.821 63.657 127.321 318.309 636.619 2 0.816 1.061 1.386 1.886 2.920 4.303 4.849 6.965 9.925 14.089 22.327 31599 3 0.765 0.978 1.250 1.638 2.353 3.182 3.482 4.541 5.841 7.453 10.215 12.924 4 0.741 0.941 1.190 1.533 2.132 2.776 2.999 3.747 4.604 5.598 7.173 8.610 5 0.727 0.920 1.156 1.476 2.015 2.571 2.757 3.365 4.032 4.773 5.893 6.869 6 0.718 0.906 1.134 1.440 1.943 2.447 2.612 3.143 3.707 4317 5.208 5.959 7 0.711 0.896 1.119 1.415 1.895 2.365 2.517 2.998 3.499 4.029 4.785 5.408 I 0.706 0.889 1.1% 1.397 1.860 2.306 2.449 2.896 3.355 3.833 4.501 5.041 9 0.703 0.883 1.100 1.383 1.1133 2.262 2.390 2.821 3.250 3.690 4.297 4.781 I. 0.700 0.879 1.093 1.372 1.812 2.228 2.359 2.764 3.169 3.581 4.144 4.587 11 0.697 0.376 1.088 1.363 1.796 2.201 2.328 2.718 3.106 3.497 4.025 4.437 12 0.695 0.873 1.083 1.356 1.782 2.179 2.303 2.681 3.055 3.428 3.930 4.318 13 0.694 0.870 1.079 1.350 1.771 2.160 2.282 2.650 3.012 3.372 3.852 4.221 14 0.692 0.868 1.076 1.345 1.761 2.145 2.264 2.624 2.977 3.326 3.787 4.140 15 0.691 0.866 1.074 1.341 1.753 2.131 2.249 2.602 2.947 3.286 3.733 4.073 16 0.690 0.865 1.071 1.337 1.746 2.131 2.235 2.583 2.921 3.252 3.686 4.01.5 17 0.689 0.863 1.069 1.333 1.740 2.110 2.224 2.567 2.898 3.222 3.646 3.965 18 0.688 0.862 1.067 1.330 1.734 2.101 2.214 2.552 2.878 3.197 3.610 3.922 19 0.688 0.861 1.066 1.328 1.729 2.093 2.205 2.539 2.861 3.174 3.579 3.883 2. 0.687 0.860 1.064 1.325 1.725 2.086 2.197 2528 2.845 3.153 3.552 3.850 21 0.686 0.859 1.063 1.323 1.721 2.080 2.189 2.518 2.831 3.135 3.527 3.819 22 0.686 0.858 1.061 1.321 1.717 2.074 2.183 2.508 2.819 3.119 3.505 3.792 23 0.685 0.858 1.060 1.319 1.714 2.069 2.177 2.500 2.807 3.104 3.485 3.768 24 0.685 0.857 1.059 1.318 1.711 2.064 2.172 2.492 2.797 3.091 3.467 3.745 25 0.684 0.856 1.058 1.316 1.708 2.060 2.167 2.485 2.787 3.078 3.450 3.725 25 0.684 0.856 1.058 1.315 1.706 2.056 2.162 2.479 2.779 3.067 3.435 3.707 27 0.684 0.855 1.057 1.314 1.703 2.052 2.158 2.473 2.771 3.057 3.421 3.690 28 0.683 0.855 1.056 1.313 1.701 2.048 2.154 2.467 2.763 3.047 3.408 3.674 29 0.683 0.854 1.055 1.311 1.699 2.045 2.150 2.462 2.756 3.038 3.396 3.659 3. 0.683 0.854 1.055 1.310 1.697 2.042 2.147 2.457 2.750 3.030 3.385 3.646 31 0.682 0.853 1.054 1.309 1.696 2.040 2.144 2.453 2.744 3.022 3.375 3.633 32 0.682 0.853 1.054 1.309 1.694 2.037 2.141 2.449 2.738 3.015 3.365 3.622 33 0.682 0.853 1.053 1.308 1.692 2.035 2.138 2.445 2.733 3.008 3.356 3.611 34 0.682 0.852 1.052 1.307 1.691 2.1.132 2.136 2.441 2.728 3.002 3.348 3.601 35 0.682 0.852 1.052 1.306 1.690 2.030 2.133 2.438 2.724 2.996 3.340 3.591 36 0.681 0.852 1.052 1.306 1.688 2.028 2.131 2.434 2.719 2.990 3.333 3.582 37 0.631 0.851 1.051 1.305 1.687 2.026 2.129 2.431 2.715 2.985 3.326 3.574 38 0.681 0.851 1.051 1.304 1.686 2.024 2.127 2.429 2.712 2.980 3.319 3.566 39 0.681 0.851 1.050 1.304 1.685 2.03 2.13 2.426 2.708 2.976 3.313 3.558 4. 0.681 0.851 1.050 1.303 1.684 2.021 2.173 2.423 2.704 2.971 3.307 3.551 50 0.679 0.849 1.047 1.299 1.676 2.009 2.109 2.403 2.678 2.937 3.261 3.496 60 0.679 0.848 1.045 1.296 1.671 2.000 2.099 2.390 2.660 2.915 3.232 3.460 70 0.678 0.847 1.044 1.294 1.667 1.994 2.093 2.381 2.648 2.899 3.211 3.435 110 0.678 0.846 1.043 1.292 1.664 1.990 2.088 2.374 2.639 2.887 3.195 3.416 90 0.677 0.846 1.042 1.291 1.662 1.987 2.084 2.368 2.632 2.878 3.183 3.402 100 0.677 0.845 1.042 1.290 1.660 1.984 2.081 2.364 2.626 2.871 3.174 3.390 1000 0.675 0.842 1.037 1.282 1.646 1.962 2.056 2.330 2.581 2.813 3.098 3.300 1 0.674 0.342 1.036 1.2132 1.645 1.960 2.054 2.326 2.576 2.307 3.090 3.291 d! 0.25 0.20 0.15 0.10 0.05 0.015 0.02 0.01 0.005 0.0075 0.001 0.0005 Are: in ight Tail 3. Determine the point estimate of the population mean and margin of error for the confidence interval. Lower bound is 19, upper bound is 31. The point estimate of the population mean is The margin of error for the condence interval is 25 6 4- A simple random sample of size n is drawn from a population that is normally distributed. The sample mean, )1, is found to be109, and the sample standard deviation, s. is found to be 10. (3) Construct an 80% condence interval about u if the sample size. n. is 211. (1:) Construct an 80% condence interval about u if the sample size. n. is 23. (c) Construct a 70% confidence interval about u if the sample size. n. is 28. gd) Could we have computed the condence intervals in parts (ch) if the population had not been normally distributed? Click the icon to view the table of areas under the tdistribution. (a) Construct an 80% condence interval about p it the sample size. n. is 211. Lower bound: 1:]: Upper bound: |: (Use ascending order. Round to one decimal place as needed.)