Percentile problems: new kinda Q in GRE

[Wildstrider]

There are 10,000 numbers, ranging from 20 to 80. If 62 is 60th percentile, then
Col A: What percentile is 74
Col B: 70th percentile

Ive got no clue on how to solve these kinda probs. Somebody please explain this guys!

[cssamal]

i think answer would be D, as nothing can be determined from the data given. As the number are between 20 to 80. 80 is 100th percentile,so 74 would lie between 60th and 100th percentile. But could not be determined.

[Penicillin]

What is "In percentile"? Does it mean that 60% of numbers are less than 62? If so, my wote is for D, because we don't know the distribution.

[jess_john]

Originally Posted by cssamal

i think answer would be D, as nothing can be determined from the data given. As the number are between 20 to 80. 80 is 100th percentile,so 74 would lie between 60th and 100th percentile. But could not be determined.

i agree with cssamal
answer D

[Wildstrider]

Thanks guys. I also feel that there is no proper solution for this problem!
Well, Im not even sure if tis right or if somethins missing or misread in the Q.
Thanks again.

[dome.gears]

20 to 80
61 spaces
1. 42 spaces brings u to 60th percentile
2. while 74 is only -6 spaces away from 100th percentile
to me it seems that -6 spaces will be nearer 100th percentile than at 60th percentile given #1.

.. but we don't know distribution so nvm.

[sweetu1995]

Can someone confirm my solution below ?

First assumption - Median is the 50th percentile (correct ??)

Now, the range is 80 - 20 = 60

So 50th percentile is at 50

Given - 62 is 60th percentile

So every 10 percentiles sees an increase of 12 (62 - 50)

So 70th percentile is (62 + 12) = 74

The two columns are equal

I am not very comfortable with percentiles and standard deviation. Hence not at all sure if what I am doing is correct

[dissa]

Originally Posted by sweetu1995

Can someone confirm my solution below ?

First assumption - Median is the 50th percentile (correct ??)

Now, the range is 80 - 20 = 60

So 50th percentile is at 50

Given - 62 is 60th percentile

So every 10 percentiles sees an increase of 12 (62 - 50)

So 70th percentile is (62 + 12) = 74

The two columns are equal

I am not very comfortable with percentiles and standard deviation. Hence not at all sure if what I am doing is correct

According to your argument,
80% = 74 + 12 = 86

But 100% would be 80 as the last number is 80.
My answer is (D)

[sweetu1995]

Ok. got it. But can I safely conclude that 50th percentile is the median ?

[dissa]

Originally Posted by sweetu1995

Ok. got it. But can I safely conclude that 50th percentile is the median ?

I don't think so. The 10,000 numbers between 20 & 80 aren't evenly distributed.