µ = 1000
σ = 200
Use the z-score formula: z = (X - μ) / σ
Assume we are 95% confident that the mean SAT score is in the top 5%. The critical value is 1.96.
1.96 = (X - 1000) / 200 → X - 1000 = 392 → X = 1392
A student can earn a minimum SAT score of 1392 in order to apply for a certain top university.