Source: Official Guide Revised GRE 2nd Ed. Part 9; Section 6; #18

1

For the seven ailments, what is the median

For the seven ailments, what is the median of the numbers of people in group 2 who have the ailments? 20, 22, 24, 26, 28

3 Explanations

2

Rupom Bhattacharjee

I am having hard times to understand the question. Can you please clarify?

Here only 240 (60% of 400) people have the 7 aliments. We have asked to find the median, approximately the 120th term. now I am unable to proceed further from here.
Can you please explain the question a little bit so that I can be sure when to find the 50% and when only the middle of the percent values?

Sep 1, 2018 • Comment

David Recine, Magoosh Tutor

Hi Rupom,

The wording of this question is a little tricky, isn't it? I'll be happy to bring you some clarity. :)

The question asks for "the median of the numbers of people in group 2 who have the ailments." Here, note that "the numbers" is plural. The number of people (singular) would be the single total number of people who have any of the 7 ailments in group 2, and that would be 60% of them. However, "the numbers" refers to the multiple numbers represented on the chart-- the seven different numbers for the seven different ailments.

So we're looking for the median of those 7 numbers. When arranged in order form smallest to largest, those 7 figures are:

3%, 4%, 5%, (6%), 10%, 11%, 21%

Notice that I've put the median of those numbers in parentheses. 6% is the median of the percentages. But remember, the percentages aren't "the numbers," strictly speaking. Instead, the percentages are proportions that REPRESENT the actual numbers of people with each illness. To find the real median number, we need to multiply the median percentage by the total number of people. 6% is our median percentage, and 6% times 400 is our actual median number of people. That would be 0.06*400, or 24.

Sep 2, 2018 • Reply

2

Anna Roberts

Sorry I really don't understand this question. Please help.
Before we always use to add the percents and find the median at 50% how come not in this case? I mean to say, add 3+4+5+6+10+11 etc and when its 50% thats where median is.

Nov 22, 2017 • Comment

Jonathan , Magoosh Tutor

Hi Radhika,
You're confusing this with a histogram chart. This chart has 7 ailments and each ailment has a percent. We know the total people in the population, so we can find the number of people who have each of the 7 ailments by multiplying the percentage by the total (400). The question is just asking for the median of these 7 values.

Nov 27, 2017 • Reply

1

Gravatar Chris Lele, Magoosh Tutor

Dec 8, 2012 • Comment

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