Step by step explanation
Lets first find the z-score for 90 in this normal distribution:
[tex]z=\frac{90-77.7}{12.1}\approx1.0165[/tex]Reviewing the table, for this value we have:
[tex]P(x>90)=0.1547[/tex]Answer
The probability that a person scored above 90 is 0.1547, that is 15.47%
