Answer Happy

A random sample of 20 chocolate energy bars of a certain brand has, on average, 220 calories per bar, with a standard deviation of 35 calories. Construct a 90% confidence interval for the true mean calorie content of this brand of energy bar. Assume that the distribution of the calorie content is approximately normal. Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. The confidence interval is<μ< (Round to one decimal place as needed.)
Standard Normal Distribution Table (Page 1) Areas under the Normal Curve .00 .01 .03 .04 .05 .06 .07 .08 0.0003 0.0005 -3.2 .02 -3.4 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 -3.3 0.0005 0.0005 0.0005 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 -3.2 0.0007 0.0007 0.0006 0.0006 0.0006 0.0006 0.0006 0.0005 0.0005 -3.1 0.0010 0.0009 0.0009 0.0009 0.0008 0.0008 0.0008 0.0008 0.0007 0.0007 -3.1 -3.0 0.0013 0.0013 0.0013 0.0012 0.0012 0.0011 0.0011 0.0011 0.0010 0.0010 -3.0 -2.9 0.0019 0.0018 0.0018 0.0017 0.0016 0.0016 0.0015 0.0015 0.0014 0.0014 -2.9 -2.8 0.0026 0.0025 0.0024 0.0023 0.0023 0.0022 0.0021 0.0021 0.0020 0.0019 -2.8 -2.7 0.0035 0.0034 0.0033 0.0032 0.0031 0.0030 0.0029 0.0028 0.0027 0.0026 -2.7 -2.6 0.0047 0.0045 0.0044 0.0043 0.0041 0.0040 0.0039 0.0038 0.0037 0.0036 -2.6 -2.5 0.0062 0.0060 0.0059 0.0057 0.0055 0.0054 0.0052 0.0051 0.0049 0.0048 -2.5 -2.4 0.0082 0.0080 0.0078 0.0075 0.0073 0.0071 0.0069 0.0068 0.0066 0.0064 -2.4 -2.3 0.0107 0.0104 0.0102 0.0099 0.0096 0.0094 0.0091 0.0089 0.0087 0.0084 -2.3 -2.2 0.0139 0.0136 0.0132 0.0129 0.0125 0.0122 0.0119 0.0116 0.0113 0.0110 -2.2 -2.1 0.0179 0.0174 0.0170 0.0166 0.0162 0.0158 0.0154 0.0150 0.0146 0.0143 -2.1 -2.0 0.0228 0.0222 0.0217 0.0212 0.0207 0.0202 0.0197 0.0192 0.0188 0.0183 -2.0 -1.9 0.0287 0.0281 0.0274 0.0268 0.0262 0.0256 0.0250 0.0244 0.0239 0.0233 -1.9 -1.8 0.0359 0.0351 0.0344 0.0336 0.0329 0.0322 0.0314 0.0307 0.0301 0.0294 -1.8 -1.7 0.0446 0.0436 0.0427 0.0418 0.0409 0.0401 0.0392 0.0384 0.0375 0.0367 -1.7 -1.6 0.0548 0.0537 0.0526 0.0516 0.0505 0.0495 0.0485 0.0475 0.0465 0.0455 -1.6 -1.5 0.0668 0.0655 0.0643 0.0630 0.0618 0.0606 0.0594 0.0582 0.0571 0.0559 -1.5 -1.4 0.0808 0.0793 0.0778 0.0764 0.0749 0.0735 0.0721 0.0708 0.0694 0.0681 1.4 -1.3 0.0968 0.0951 0.0934 0.0918 0.0901 0.0885 0.0869 0.0853 0.0838 0.0823 -1.3 -1.2 0.1151 0.1131 0.1112 0.1093 0.1075 0.1056 0.1038 0.1020 0.1003 0.0985 -1.2 -1.1 0.1357 0.1335 0.1314 0.1292 0.1271 0.1251 0.1230 0.1210 0.1190 0.1170 -1.1 -1.0 0.1587 0.1562 0.1539 0.1515 0.1492 0.1469 0.1446 0.1423 -0.9 0.1841 0.1814 0.1788 0.1762 0.1736 0.1711 0.1685 0.1660 0.1635 0.1611 -0.9 -0.8 0.2119 0.2090 0.2061 0.2033 0.2005 0.1977 0.1949 0.1922 0.1894 0.1867 -0.8 -0.7 0.2420 0.2389 0.2358 0.2327 0.2296 0.2266 0.2236 0.2206 0.2177 0.2148 -0.7 -0.6 0.2743 0.2709 0.2676 0.2643 0.2611 0.2578 0.2546 0.2514 0.2483 0.2451 -0.6 -0.5 0.3085 0.3050 0.3015 0.2981 0.2946 0.2912 0.2877 0.2843 0.2810 0.2776 -0.5 -0.4 0.3446 0.3409 0.3372 0.3336 0.3300 0.3264 0.3228 0.3192 0.3156 0.3121 -0.4 -0.3 0.3821 0.3783 0.3745 0.3707 0.3669 0.3632 0.3594 0.3557 0.3520 0.3483 -0.3 -0.2 0.4207 0.4168 0.4129 0.4090 0.4052 0.4013 0.3974 0.3936 0.3897 -0.1 0.4602 0.4562 0.4522 0.4483 0.4443 0.4364 -0.0 0.5000 0.4960 0.4920 0.4880 0.1401 0.1379 -1.0 0.3859 -0.2 0.4404 0.4325 0.4286 0.4247 -0.1 0.4840 0.4801 0.4761 0.4721 0.4681 0.4641 -0.0 z z .00 .01 .02 .03 .04 .05 .06 .07 .08 .09 .09 0.0002 -3.4 0.0003 -3.3
Standard Normal Distribution Table (Page 2) Areas under the Normal Curve .00 .01 .03 .04 .05 .06 .07 .08 .09 z 0.5359 0.0 0.1 0.8708 0.8729 0.8907 0.9066 0.9082 0.9222 0.9236 0.9251 0.9265 1.5 0.9332 0.9345 0.9357 1.5 1.6 .02 0.0 0.5000 0.5040 0.5080 0.5120 0.5160 0.5199 0.5239 0.5279 0.5319 0.1 0.5398 0.5438 0.5478 0.5517 0.5557 0.5596 0.5636 0.5675 0.5714 0.5753 0.2 0.5793 0.5832 0.5871 0.5910 0.5948 0.5987 0.6026 0.6064 0.6103 0.6141 0.2 0.3 0.6179 0.6217 0.6255 0.6293 0.6331 0.6368 0.6406 0.6443 0.6480 0.6517 0.3 0.4 0.6554 0.6591 0.6628 0.6664 0.6700 0.6736 0.6772 0.6808 0.6844 0.6879 0.4 0.5 0.6915 0.6950 0.6985 0.7019 0.7054 0.7088 0.7123 0.7157 0.7190 0.7224 0.5 0.6 0.7257 0.7291 0.7324 0.7357 0.7389 0.7422 0.7454 0.7486 0.7517 0.7549 0.6 0.7 0.7580 0.7611 0.7642 0.7673 0.7704 0.7734 0.7764 0.7794 0.7823 0.7852 0.7 0.8 0.7881 0.7910 0.7939 0.7967 0.7995 0.8023 0.8051 0.8078 0.8106 0.8133 0.8 0.9 0.8159 0.8186 0.8212 0.8238 0.8264 0.8289 0.8315 0.8340 0.8365 0.8389 0.9 1.0 0.8413 0.8438 0.8461 0.8485 0.8508 0.8531 0.8554 0.8577 0.8599 0.8621 1.0 1.1 0.8643 0.8665 0.8686 0.8749 0.8770 0.8790 0.8810 0.8830 1.1 1.2 0.8849 0.8869 0.8888 0.8925 0.8944 0.8962 0.8980 0.8997 0.9015 1.2 1.3 0.9032 0.9049 0.9099 0.9115 0.9131 0.9147 0.9162 0.9177 1.3 1.4 0.9192 0.9207 0.9279 0.9292 0.9306 0.9319 1.4 0.9370 0.9382 0.9394 0.9406 0.9418 0.9429 0.9441 0.9452 0.9463 0.9474 0.9484 0.9495 0.9505 0.9515 0.9525 0.9535 0.9545 1.6 1.7 0.9554 0.9564 0.9573 0.9582 0.9591 0.9599 0.9608 0.9616 0.9625 0.9633 1.7 1.8 0.9641 0.9649 0.9656 0.9664 0.9671 0.9678 0.9686 0.9693 0.9699 0.9706 1.8 1.9 0.9713 0.9719 0.9726 0.9732 0.9738 0.9744 0.9750 0.9756 0.9761 0.9767 1.9 2.0 0.9772 0.9778 0.9783 0.9788 0.9793 0.9798 0.9803 0.9808 0.9812 0.9817 2.0 2.1 0.9821 0.9826 0.9830 0.9834 0.9838 0.9842 0.9846 0.9850 0.9854 0.9857 2.1 2.2 0.9861 0.9864 0.9868 0.9871 0.9875 0.9878 0.9881 0.9884 0.9887 0.9890 2.2 2.3 0.9893 0.9896 0.9898 0.9901 0.9904 0.9906 0.9909 0.9911 0.9913 0.9916 2.3 2.4 0.9918 0.9920 0.9922 0.9925 0.9927 0.9929 0.9931 0.9932 0.9934 0.9936 2.4 2.5 0.9938 0.9940 0.9941 0.9943 0.9945 0.9946 0.9948 0.9949 0.9951 0.9952 2.5 2.6 0.9953 0.9955 0.9956 0.9957 0.9959 0.9960 0.9961 0.9962 0.9963 0.9964 2.6 2.7 0.9965 0.9966 0.9967 0.9968 0.9969 0.9970 0.9971 0.9972 0.9973 0.9974 2.7 2.8 0.9974 0.9975 0.9976 0.9977 0.9977 0.9978 0.9979 0.9979 0.9980 0.9981 2.9 0.9981 0.9982 0.9982 0.9983 0.9984 0.9984 0.9985 0.9985 0.9986 0.9986 3.0 0.9987 0.9987 0.9987 0.9988 0.9988 0.9989 0.9989 0.9989 0.9990 0.9990 3.1 0.9990 0.9991 0.9991 0.9991 0.9992 0.9992 0.9992 0.9992 0.9993 0.9993 3.2 0.9993 0.9993 0.9994 0.9994 0.9994 0.9994 0.9994 0.9995 0.9995 0.9995 3.3 0.9995 0.9995 0.9995 0.9996 0.9996 0.9996 0.9996 0.9996 3.4 0.9997 0.9997 0.9997 0.9997 0.9997 0.9997 0.9997 .00 .01 .02 .03 .04 .05 2.8 2.9 0.9996 0.9997 0.9997 0.9997 0.9998 .06 .07 .08 .09 3.0 3.1 3.2 3.3 3.4
Critical Values of the t-Distribution (Page 1) Critical Values of the t-Distribution t 1 21346 5 67990 8 21 22 23 24 25 0.40 0.325 0.289 0.277 29 30 0.271 0.267 16 17 18 19 20 0.257 40 60 120 0.265 0.263 0.262 0.261 0.260 10 11 0.260 12 0.259 13 0.259 14 0.258 0.537 15 0.258 T 26 0.256 27 0.256 28 0.256 0.256 0.256 0.30 0.727 0.617 0.584 0.569 0.559 0.553 0.549 0.546 0.543 0.542 0.20 1.376 1.061 0.978 0.941 0.15 0.10 0.05 1.963 3.078 6.314 1.386 1.886 2.920 1.250 1.638 2.353 1.190 1.533 2.132 0.920 1.156 1.476 2.015 0.540 0.876 0.539 0.873 0.538 0.870 0.258 0.257 0.257 0.534 0.862 0.257 0.533 0.861 0.533 0.860 0.906 0.896 0.889 0.883 0.879 0.868 0.536 0.866 0.257 0.256 0.256 0.532 0.256 0.531 0.256 0.531 0.535 0.865 0.534 0.863 0.255 0.529 0.254 0.527 0.254 0.526 0.253 0.524 0.40 0.30 1.134 1.119 1.108 1.100 1.093 1.088 1.083 1.079 1.076 1.074 0.851 0.848 0.845 0.842 0.20 1.071 1.069 1.067 1.066 1.064 0.531 0.856 0.531 0.855 0.530 0.855 0.530 0.854 1.055 0.530 0.854 1.055 0.532 0.859 1.063 0.532 0.858 1.061 0.858 1.060 0.857 1.059 0.856 1.058 1.316 1.058 1.057 1.056 1.050 1.045 1.440 1.415 1.397 1.383 1.372 1.041 1.036 0.15 a 1.363 1.356 1.350 1.345 1.341 1.323 1.321 1.319 1.318 1.337 1.746 1.333 1.740 1.330 1.328 1.325 1.315 1.314 1.313 1.311 1.310 1.943 1.895 1.860 1.833 1.812 1.303 1.296 1.289 1.282 0.10 1.796 1.782 1.771 1.761 1.753 1.734 1.729 1.725 1.721 1.717 1.714 1.711 1.708 1.706 1.703 1.701 1.699 1.697 1.684 1.671 1.658 1.645 0.05 0.025 12.706 4.303 3.182 2.776 2.571 2.447 2.365 2.306 2.262 2.228 2.201 2.179 2.160 2.145 2.131 2.120 2.110 2.101 2.093 2.086 2.080 2.074 2.069 2.064 2.060 2.056 2.052 2.048 2.045 2.042 2.021 2.000 1.980 1.960 0.025 I
Critical Values of the t-Distribution (Page 2) Critical Values of the t-Distribution V 1 2 3 4 10 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 0.02 15.894 4.849 3.482 2.999 2.757 40 60 120 ∞ 2.612 2.517 2.449 2.398 2.359 2.328 2.303 2.282 2.264 2.249 2.235 2.224 2.214 2.205 2.197 2.189 2.183 2.177 2.172 2.167 26 2.162 27 2.158 28 2.154 29 2.150 30 2.147 2.123 2.099 2.076 2.054 0.02 0.015 21.205 5.643 3.896 3.298 3.003 2.829 2.715 2.634 2.574 2.527 2.491 2.461 2.436 2.415 2.397 2.382 2.368 2.356 2.346 2.336 2.328 2.320 2.313 2.307 2.301 2.296 2.291 2.286 2.282 2.278 0.01 31.821 6.965 4.541 3.747 3.365 3.143 2.998 2.896 2.821 2.764 2.718 2.681 2.650 2.624 2.602 2.583 2.567 2.552 2.539 2.528 2.518 2.508 2.500 2.492 2.485 2.479 2.473 2.467 2.462 2.457 2.250 2.423 2.223 2.390 2.196 2.358 2.170 2.326 0.015 0.01 0.0075 42.433 8.073 5.047 3.634 3.372 3.203 3.085 2.998 2.932 2.879 2.836 2.801 2.771 2.746 2.724 2.706 2.689 2.674 2.661 2.649 2.639 2.629 2.620 2.612 2.605 2.598 2.592 2.586 2.581 2.542 2.504 2.468 2.432 0.0075 0.005 63.656 9.925 5.841 4.604 4.032 3.707 3.499 3.355 3.250 3.169 3.106 3.055 3.012 2.977 2.947 2.921 2.898 2.878 2.861 2.845 2.831 2.819 2.807 2.797 2.787 2.779 2.771 2.763 2.756 2.750 2.704 2.660 2.617 2.576 0.005 0.0025 127.321 14.089 7.453 5.598 4.773 4.317 4.029 3.833 3.690 3.581 3.497 3.428 3.372 3.326 3.286 3.252 3.222 3.197 3.174 3.153 3.135 3.119 3.104 3.091 3.078 3.067 3.057 3.047 3.038 3.030 2.971 2.915 2.860 2.807 0.0025 0.0005 636.578 31.600 12.924 8.610 6.869 5.959 5.408 5.041 4.781 4.587 4.437 4.318 4.221 4.140 4.073 4.015 3.965 3.922 3.883 3.850 3.819 3.792 3.768 3.745 3.725 3.707 3.689 3.674 3.660 3.646 3.551 3.460 3.373 3.290 0.0005 I