A company that provides coaching for the SAT claims in one of its ads: "90% of our students improve their SAT scores after attending our course." To check the company's claim, 500 students who took the company's course were sampled and it was found that 407 of them (81.4%) actually improved their SAT scores after attending the course. Based on the sample results, we have some serious doubts regarding the accuracy of the company's claim.