Given:
μ = 70, the mean
σ = 10, the standard deviation
The random variable is x = 65.
Calculate the z-score.
z = (x - μ)/σ = (65 -70)/10 = - 0.5
From standard ables, obtain
P(x<5) = 0.3085 ≈ 30%
The score of 65 is in the 30th percentile.
Answer: 30th
