Thinkin : 1. Two Data Management Courses offered at CCH last year had different class averages. One class had an average of 75 with 24 students with the overall average of both classes as 71. If the second class had 32 students what was its average? Give answer to 2 decimal places. 2. . IQ scores of people in Canada are normally distributed with a mean of 105 and a standard deviation of 12? (a) What percent of Canadians have an IQ lower (b) What percent of Canadians have an IQ greater than 120? Use your Z-Score table. than 140? (Are considered Genius]? 3. CCH purchased batteries for their hi-tech calculators with a mean lifespan of 920 hours and a standard deviation of 250 hours, in how many hours would 75% of the batteries need replacing. Give an answer to the nearest unit. Again use your Zscore table. Table of Standard Normal Probabilities for Negative Z-scores Table of Standard Normal Probabilities for Positive Z-scores 0.04 0.05 0.06 0.07 0.08 0.09 0.00 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.00 0,01 0.02 0.03 -3.4 0.0003 0.0003 0.0003 0.0903 0.0003 0.0005 0.0003 0.0003 0.0003 0.0002 0.0 0.500D 0.5040 0.5080 0.5120 0.5160 0.5199 0.5239 0.5279 0.5319 0.5359 0.5517 0.5557 0.5596 0.3636 0.5675 0.5714 0.5753 -3.3 0,0005 0.0005 0,0005 0,0004 0.0004 0.0004 0,0004 0.0004 0.0004 0,0003 0.1 0.5398 0.5438 0.5478 0.5910 0.5948 0.5987 0.6026 0.6064 0.6103 0.6141 -32 0,0007 0.0007 0.0006 0,0006 0.0006 0.0006 0.0006 0,0005 0.0005 0.0005 0.2 0.5793 0.5832 0.5871 0.6331 0.6368 0.6406 0.6443 0.6480 0.6517 -3.1 0.0010 0.0009 0.0009 0.0009 0.0008 0.0008 0.0008 0.0008 0.0007 0.0007 0.3 0.6179 0.6217 0.6255 0.6293 D.4 0.6591 0.6628 0.6664 0.6700 0.6736 0.6772 0.6808 0.6844 0.6879 -3.0 0.0013 0.0013 0.0013 0.0012 0.0012 0.001 1 0.001 1 0.0011 0.0010 0.0010 0,6554 0.7224 -2.9 0.0019 0.0018 0.0018 0.0017 0.0016 0.0016 0,0015 0,0015 0.0014 0.0014 0.5 0.6915 0.6950 0.6985 0.7019 0.7054 0.7088 0.7123 0.7137 0.7190 0.7357 0.7389 0.7422 0.7454 0.7486 0.7517 0.7549 -2.8 0.0026 0.0025 0.0024 0,0023 0.0023 0.0022 0,0021 0,0021 0.0020 0.0015 0.6 0.7257 0.7291 0.7324 0.7734 0.7764 0.7794 0.7823 0.7852 -2.7 0.0035 0.0034 0.0033 0.0032 0.0031 0.0030 0.0029 0.0028 0.0027 0.0026 0.7 0.7580 0.7611 0.7642 0.7673 0.7704 0.0045 0.0044 0.0043 0.0041 0.0040 0.0039 0.0038 0.0037 0.0036 D.8 0,7881 0.7910 0.7939 0.7967 0.8023 0.8051 0.8078 0.8106 0.8133 -2.6 0.0047 0.0062 0.0060 0,0059 0.0057 0.0055 0.0054 0.0052 0.0051 0.0049 0.0048 0.9 0.8159 0.8186 0.8212 0.8238 0.8264 0.8289 0.8315 0.8340 0.8365 0.8389 -2.5 0.0075 0.0073 0.0071 1.0069 0.0068 0.0066 0.0064 1.0 0.8413 0.8438 0.8461 0,8485 0.8508 0.8531 0.8554 0.8577 0.8599 0.8621 -2.4 0.0082 0.0080 0.0078 0.0087 0.0084 1.1 0.8643 0.8665 0.8686 0.8708 0.8729 0.8749 0.8770 0.8790 0.8810 0.8830 -2.3 0,0107 0.0104 0.0102 0,0099 0.0096 0.0094 0,0091 0.0089 -2.2 0.0139 0.0136 0.0132 0,0129 0.0125 0.0122 0,01 19 0,01 16 0,0113 0.0110 1.2 0,8849 0.8869 0.8888 0,8907 0,8925 0.8944 0.8962 0,8980 0,8997 0.9015 0,0166 0.0162 0.0158 0.0154 0,0150 0.0146 0.0143 1.3 0.9032 0.9049 0.9066 0.9082 0.9099 0.91 15 0.9131 0.9147 0.9162 0.9177 -2.1 0,0179 0.0174 0,0170 -20 0.0228 0.0222 0.0217 0.0212 0.0207 0.0202 0.0197 0.0192 0.0188 0.0183 1.4 0.9192 0.9207 0.9222 0.9236 0.9251 0.9265 0.9279 0.9292 0.9306 0.9319 0.0287 0.0281 0,0274 0,0268 0.0262 0.0256 0.0250 0.0244 0.0239 0.0233 1.5 0,9332 0.9345 0.9357 0,9370 0,9382 0.9394 0.9406 0.9418 0.9429 0.9441 -1.9 0,0314 0.0294 1.6 0,9452 0.9463 0.9474 0,9484 0,9495 0.9505 0.9515 0,9525 0.9535 0.9545 -1.8 0.0359 0.0351 0.0344 0,0336 0.0329 0.0322 0,0307 3,0301 0.9582 0.9599 0.9608 0,9616 0.9625 0.9633 -1.7 0.0446 0.0436 0.0427 0,0418 0.0409 0.0401 0,0392 0,0384 0.0375 0.0367 1.7 0,9554 0.9564 0.9573 0.9591 0,9693 0.9699 0.9706 -1.6 0.0548 0.0537 0.0526 0,0516 0.0505 0.0495 0.0485 0.0475 0.0465 0.045 1.8 0,9641 0.96-49 0.9656 0.9664 0.9671 0.9678 0.9686 0.0606 0.0594 0,0582 0.0571 0.0559 1.9 0,9713 0.9719 0.9726 0.9732 0,9738 0.9744 0.9750 0.9756 0,9761 0.9767 -15 0.0668 0.0655 0.0643 0,0630 0.0618 0,9808 0,9812 0.9817 -1.4 0,0808 0.0793 0.0778 0,0764 0.0749 0.0735 0.0721 0,0708 0.0694 0.0681 2.0 0,9772 0.9778 0.9783 0,9788 0,9793 0.9798 0.9803 0.08.53 0.0838 0.0823 2.1 0,9821 0.9826 0.9830 0.9834 0,9838 0.9842 0.9846 0,9850 0.9854 0.9857 -1.3 0.0968 0.0951 0,0934 0,0918 0.0901 0.0885 0.0869 0.1075 0.1056 0.1038 0,1020 0.1003 0.0985 2.2 0,9861 0.9864 0.9868 0,9871 0.9875 0.9878 0.9881 0.9884 0.9887 0.9890 0.1151 0.1131 0.1112 0,1093 0,9893 0.9896 0.9898 0.9901 0.9904 0.9906 0.9909 0.9911 0.9913 0.9916 -1.1 0.1357 0.1335 0.1314 0.1292 0.1271 0.1251 0.1230 0.1210 0.1 190 0.1170 2.3 0,9934 0.9936 -1,0 0.1587 0.1562 0.1539 0.1515 0.1492 0.1469 0.1446 0.1423 0.1401 0.1379 2.4 0,9918 0.9920 0.9922 1,9925 0,9027 0.9929 0.9931 0.9932 -0.9 0.1841 0.1814 0.1788 0,1762 0.1736 0.1711 D. 1685 0.1660 0.1635 0.1611 2.5 0,9938 0.9940 0.9941 0.9043 0.9945 0.9946 0,9948 0.9949 0.9951 0.9952 0.1949 0.1922 0.1894 0.1867 2.6 0,9953 0).9955 0.9956 0.9957 0.9959 0.9960 0.9961 0.9962 0.9963 0.996- -0.8 0.2119 0.2090 0.2061 0.2033 0.2005 0.1977 0.2177 0.2148 2.7 0,9965 0.9960 0.9967 0.9068 0.995 0.9970 0.9971 0,9972 0.9973 0.9974 -0.7 0.2420 0.2389 0.2358 0.2327 0.2296 0.2266 0.2236 0.2206 0.2743 0.2709 0.2676 0.2643 0.2611 0.2578 0.2546 0.2514 0.2483 0.2451 2.8 0,9974 0.9975 0.9976 0.9977 0.9977 0.9978 0.9979 0,9979 0.9980 0.998 1 -0.6 0.3050 0.3015 0.2981 0.2946 0.2912 0.2877 0.2843 0.2810 0.2776 2.9 0,9981 0.9982 0.9982 0.9983 0,9984 0.9984 0.9985 0.9085 0.9986 0.9986 -0.5 0.3085 0.9990 -0,4 0.3446 0.3409 0.3372 0,3336 0.3300 0.3264 0.3228 0.3192 0.3156 0.3121 3.0 0.9987 0.9987 0.9987 0.9988 0.998 8 0.9989 0.9989 0.9989 0.9990 0,3707 0.3669 0. 3632 0.3594 0.3557 0.3520 0.3483 3.1 0,9990 0.9991 0.9991 0.9991 0,9992 0.9992 0,9092 0,9992 0.9993 0.999 -0,3 0.3821 0.3783 0.3745 0.9995 -0.2 0,4207 0.4168 0.4129 0,4090 0.4052 0.4013 0.3974 0.3936 0.389 0.3859 3.2 0,9993 0.9993 0.9094 0.9994 0,9994 0.9994 0.9094 0,9095 0.9995 0,9996 0,9996 0.9997 -0.1 0.4602 0.4562 0,4522 0,4483 0.4443 0.4404 0,4364 0,4325 0.4286 0.4247 3.3 0,9995 0.9995 0.9995 0,9996 0.9996 0.9996 0.9996 0,9997 0,9997 0.9997 0.9997 0,9997 0.9997 0.9998 -0,0 0,5000 0.4960 0.4920 0,4880 0.4840 0.4801 0.4761 0,4721 0.4681 0.4641 1.4 0,9997 0.9997 0.9997 Note that the probabilities given in this table represent the area to the LEFT of the z-score. The area to the RIGHT of a z-score = 1 - the area to the LEFT of the z-score