Question

Scores on the Welcher Adult Intelligent Scale (a standard IQ test) for the 20 to 34 age group are approximately normally distributed with μ=110 and σ=25. At what percentile is an IQ score of 150? (meaning at most 150, less than 150, or x ≤150). NOTE: μ is the population mean, and σ is the population standard deviation. Z= (x-μ)/σ and x is the score.Required to answer.Single choice.Immersive Reader

Answer 1

94.52% or 94.52 percentile

Explanation:

Z= (x-μ)/σ

μ is the population mean, and σ is the population standard deviation.

μ=110 and σ=25, x = 150( IQ score)

Z = 150 - 110/25

= 40/25

Z = 1.6

Probability value from Z-Table:

P(x≤ 150) = 0.9452

Converting to percentage = 0.9452 × 100

= 94.52% or 94.52 percentile