Calculate the mean score. This is the average score on the test. Simply add all the scores and divide by the number of tests. For example, assume that of 10 students taking an exam, the test scores are 70, 50, 90, 95, 100, 80, 87, 66, 88 and 98. Add together the scores to get 824, then divide by 10, which equals a mean score of 82.4. Call this X0.
Determine where you want the mean score to be. In the example, assume you want the mean to be an 87. Call this Y0.
Pick where you want the low or high score to be and then pick the corresponding grade on the test. In the example, assume you want a low score of 65. Call this X1. The lowest on the test is 50. Call this Y1.
Subtract Y1 from Y0. Subtract X1 from X0. In the example, 87 minus 50 equals 37. Label this the numerator. Then, 82.4 minus 65 equals 17.4 Call this the denominator.
Divide the numerator by the denominator. In the example, 37 divided by 17.4 equals 2.1264.
Subtract the student's score from X0 or vice versa to make the number positive. In the example, if using the 87 score, then 87 minus 82.4 equals 4.6.
Multiply the result in Step 5 by the result in the previous step. In the example, 2.1264 times 4.6 equals 9.7814.
Add the result from Step 7 to Y0. In the example, 87 plus 9.7814 equals 96.7814, or 97. This is a 10-point curve for the student.