sandy wrote:

In a distribution of 850 different measurements, x centimeters is at the 73rd percentile. If there are 68 measurements in the distribution that are greater than y centimeters but less than x centimeters, then y is approximately at what percentile in the distribution?

A. 45th

B. 50th

C. 55th

D. 60th

E. 65th

In a distribution of 850 different measurements, x centimeters is at the 73rd percentile. 73% of 850 = 620.5, which is approximately 621

So, we know that approximately 621 measurements are less than x (and the other 229 measurements are greater than x).

We might sketch it as follows:

-------621 measurements----------x------229 measurements

There are 68 measurements in the distribution that are greater than y centimeters but less than x centimeters We can add this to our sketch as follows:

-------553 measurements-------y----68 measurements----x------229 measurements

Notice that there are 621 measurements less than x, AND there are 68 measurements between y and x.

621 - 68 = 553 .

So, we can conclude that 553 measurements are less than y

y is approximately at what percentile in the distribution?553 of the 850 measurements are less than y.

553/850 ≈ 65%

Answer: E

_________________

Brent Hanneson – Founder of greenlighttestprep.com

Brent also tutors students for the GRE