Question

SAT scores are normally distributed, with a mean of 500 points and a standard deviation of 100 points. Suppose you take the SAT. Several weeks later, you receive your results, which show that you reached the 80th percentile for the math portion.

Recalling that SAT scores are always expressed as multiples of 10, how many points did you get on the test?

Answer 1

580

Explanation:

Apex

Answer 2

The solution to the problem is as follows:

Let be X: scores of SAT

P(X ≥ x) = 0.9

P((X - 500)/100 ≥ (x - 500)/100) = 0.9

P(Z ≥ z) = 0.9

z = 1.28

1.28 = (x - 500)/100

128 + 500 = x

x = 628

I hope my answer has come to your help. God bless and have a nice day ahead!