Khan Academy offered a free 20-hour SAT Practice. According to some research by the College Board (2017), the organization behind the SAT, studying for the SAT for 20 hours on free Official SAT Practice of Khan Academy is associated with an average score gain of 115 points. The average score gain is based on a sample of students who took the PSAT/NMSQT and then the SAT, and it may not reflect the true population of test takers. After the Khan Academy course showed an average score increase of 115 points, some companies switched their position. Test-preparation organizations like Kaplan, Princeton Review, etc. advertised their services by claiming that students gain, overall, 100 or more points on the Scholastic Achievement Test (SAT). According to a study by the National Association of College Admission Counseling (NACAC), SAT prep courses raised critical reading scores by about 10 points and math scores by about 20 points (Grove, 2019). The 2017 report detailing the results of Khan Academy SAT test preparation has a sample size of approximately 250,000, average score increase 115 points, and 16,000 participants gained 200 or more points. Assuming this data is normally distributed, what is the probability of 100 or more points? Do you think that taking one of the Kaplan, Princeton Review, etc. classes would give a test taker 100 or more points? How might this be a biased statistic? Clayton, M. (1998). Does paid prep raise SAT scores? The Christian Science Monitor. Retrieve