Question

The average score on a standardized test is 500 points with a standard deviation of 50 points. What is the probability that a student scores more than 400 on the standardized test?

Answer 1

The average score is 500 points and the standard deviation is 50 points.Mean - 2 SD = 500 - 2 * 50 = 500 - 100 = 400It means that more than 400 on the standardized test is more than: Mean - 2 Standard deviations.For the Normal distribution: 100% - 2.5 % = 97.5% = 0.975.Answer: The probability that student scores more than 400 points is 0.975.