An aptitude test has a mean score of 80 and a standard deviation of 5.The population of scores is normally distributed.What raw score corresponds to the 70^th percentile? A)77.4 B)83.5 C)82.6 D)76.5

Question

Quizplus · Accepted Answer

Using the z-score formula, we can calculate the z-score corresponding to the 70th percentile: 
z = invNorm(0.70) ≈ 0.5244

We can then use the formula for transforming a z-score to a raw score: 
z = (X - μ) / σ

Rearranging this formula to solve for X: 
X = z * σ + μ

Plugging in the given values: 
X = 0.5244 * 5 + 80 ≈ 82.62

Therefore, the raw score corresponding to the 70th percentile is approximately 82.62. The closest answer choice is C, 82.6.

An Aptitude Test Has a Mean Score of 80 and a Standard