1423b4d4a23d24131413234123a243a2413a21441343 18. db4abadcacb1dad3141ac212a3a1c3a144ba2db41b43 19. db2a33dcacbd32d313c21142323cc300000000000000 20. 1b33b4d4a2b1dadbc3ca22c000000000000000000000 21. d12443d43232d32323c213c22d2c23234c332db4b300 22. d4a2341cacbddad3142a2344a2ac23421c00adb4b3cb     Take a look at the answers in bold. Did fifteen out of twenty-two students somehow manage to reel off the same six consecutive correct answers (the d-a-d-b-c-b string) all by themselves? There are at least four reasons this is unlikely. One: those ques- tions, coming near the end of the test, were harder than the earlier questions. Two: these were mainly subpar students to begin with, few of whom got six consecutive right answers elsewhere on the test, mak- ing it all the more unlikely they would get right the same six hard questions. Three: up to this point in the test, the fifteen students an- swers were virtually uncorrelated. Four: three of the students (num- bers 1, 9, and 12) left at least one answer blank before the suspicious string and then ended the test with another string of blanks. This sug- gests that a long, unbroken string of blank answers was broken not by the student but by the teacher. There is another oddity about the suspicious answer string. On     nine of the fifteen tests, the six correct answers are preceded by an- other identical string, 3-a-1-2, which includes three of four incorrect answers. And on all fifteen tests, the six correct answers are followed by the same incorrect answer, a 4. Why on earth would a cheating teacher go to the trouble of erasing a students test sheet and then fill in the wrong answer? Perhaps she is merely being strategic. In case she is caught and hauled into the principals office, she could point to the wrong an-