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% of distribution is approximately more than x + s?

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% of distribution is approximately more than x + s?

by gmattesttaker2 » Sun Feb 23, 2014 4:23 pm
Hello,

Can you please tell me how to solve this:

The heights of students at a certain college are symmetrically distributed to both sides of the
mean x. If 34 percent of the distribution lies at more than one standard deviation s from the
mean, what percent of the distribution is approximately more than x + s?

(A) 94%
(B) 68%
(C) 46%
(D) 32%
(E) 16%

OA: E

Thanks,
Sri
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by theCodeToGMAT » Sun Feb 23, 2014 8:36 pm
First Standard Deviation is at 34%

Remaining = 50% - 34% = 16%
[spoiler]
{E}[/spoiler]
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by Nupur.nk » Mon Feb 24, 2014 4:13 am
gmattesttaker2 wrote:Hello,

Can you please tell me how to solve this:

The heights of students at a certain college are symmetrically distributed to both sides of the
mean x. If 34 percent of the distribution lies at more than one standard deviation s from the
mean, what percent of the distribution is approximately more than x + s?

(A) 94%
(B) 68%
(C) 46%
(D) 32%
(E) 16%

OA: E

Thanks,
Sri
Assume that there are 100 students. Then 50 students are on the lower end of the mean and 50 of them
are on the higher end of the mean. Thus, if, more than x + s is @ 36%, then x + s is @ 50-36= 16%

Cheers !

Nupur
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by gmattesttaker2 » Thu Feb 27, 2014 10:40 pm
theCodeToGMAT wrote:First Standard Deviation is at 34%

Remaining = 50% - 34% = 16%
[spoiler]
{E}[/spoiler]
Hi Rahul,

I am not very clear with this First Standard Deviation. Can you just explain it again?

Thanks,
Sri
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by theCodeToGMAT » Thu Feb 27, 2014 10:46 pm
gmattesttaker2 wrote:
theCodeToGMAT wrote:First Standard Deviation is at 34%

Remaining = 50% - 34% = 16%
[spoiler]
{E}[/spoiler]
Hi Rahul,

I am not very clear with this First Standard Deviation. Can you just explain it again?

Thanks,
Sri
Sri, there's a pattern of percentage in Standard Deviation.
First Standard Deviation happens at approx 34%
Second happens at approx 14%
and third at approx 2%

Also, this information was in accordance with the question stem.
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by Brent@GMATPrepNow » Fri Feb 28, 2014 6:29 am
theCodeToGMAT wrote:
gmattesttaker2 wrote:
theCodeToGMAT wrote:First Standard Deviation is at 34%

Remaining = 50% - 34% = 16%
[spoiler]
{E}[/spoiler]
Hi Rahul,

I am not very clear with this First Standard Deviation. Can you just explain it again?

Thanks,
Sri
Sri, there's a pattern of percentage in Standard Deviation.
First Standard Deviation happens at approx 34%
Second happens at approx 14%
and third at approx 2%

Also, this information was in accordance with the question stem.
I should point out that the ranges above are for NORMAL distributions only. Other kinds of distributions do not have the same configuration. Also note that Normal distributions are not tested on the GMAT.

I should also note that the original question (below), is not well worded.
The heights of students at a certain college are symmetrically distributed to both sides of the
mean x. If 34 percent of the distribution lies at more than one standard deviation s from the
mean, what percent of the distribution is approximately more than x + s?

(A) 94%
(B) 68%
(C) 46%
(D) 32%
(E) 16%
34 percent of the distribution lies at more than one standard deviation s from the mean
This is very ambiguous. Based on the given answer, I'm assuming that this should read, "34 percent of the distribution lies BETWEEN the mean and one standard deviation (s) GREATER than the mean"

Given its problems, I suggest that you skip this question altogether and move on to actual GMAT-quality questions.

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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