Normal distribution is when 50 percent of a quantity appears to the right of the halfway mark and 50 percent falls to the left. Used for phenomena such as blood pressure readings and height, the data can be depicted on a horizontal line and the quantity of data depicted on the vertical line. This arrangement forms a bell-shaped pattern called a normal curve, according to Regents Exam Prep Center.Continue Reading
A normal distribution or bell curve is arranged symmetrically on either side of the mean (sometimes the median is used). Some teachers grade their students' exams on a bell curve, according to K12 Academics. This is a method of assigning a grade score that is relative to other students' performance. The teacher decides which grade represents the mean, or median, and then assigns grades by following the normal distribution. More often applied at the university level rather than in the lower grades, bell-curve grading usually involves the choice of C as the median grade.
Another way of grading on a curve that does not necessary adhere to the bell curve model is to calculate the difference between the highest possible score and the highest actual score and then add that amount to each student's grade. This method adjusts for exam questions that may be too difficult without ignoring the top student's superior performance.Learn more about Statistics