Answer:
0.00135
Step-by-step explanation:
Given that :
Mean, μ = 400
Standard deviation, σ = 40
Approximate percentage of students above 520 ;
Using the relation :
Z = (x - mean) / standard deviation
P(x > 520)
Zscore = (520 - 400) / 40
Zscore = 120 / 40
Z = 3
P(Z > 3) = 1 - P(Z < 3)
P(Z < 3) = 0.99865 (Z probability calculator)
1 - 0.99865 = 0.00135
