Question

1) The Graduate Record Examination (GRE) is a standardized test that students usually take before entering graduate school. According to the document Interpreting Your GRE Scores, a publication of the Educational Testing Service, the scores on the verbal portion of the GRE are approximately normally distributed with a mean of 462 points and a standard deviation of 119 points. Find the 90th percentile for this exam score.  Please show your work, and steps. If there is a bell curve write one.

Answer 1

Solution: We are given:

$\boldsymbol{\mu=462, \sigma=119}$

Let x be the 90th percentile for this exam score.

We have to find the z-value corresponding to area = 0.90. Using the standard normal table, we have:

$\boldsymbol{z(0.90)=1.28 }$

The excel function to find this value is:

$\boldsymbol{=NORMSINV(0.90)}$

Now using the z-score formula, we have:

1 - U

$1.28= \frac{x-462}{119}$

$1.28 \times 119= x-462$

$x=462+152.32$

$\boldsymbol{x=614.32 }$

Therefore, the 90th percentile for this exam score is 614.32

0.90 X=614.32