Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

It is D. If mean=max value it means that all values are equal and STD deviation is 0

Should be B then?

I think that all you have to know about Standard deviation is that it is a measure of dispersion around the mean value.
If the range is 0, it means that MAX-MIN=0, or MAX value=Min Value. The deviation is obviously 0.
If the mean is = to MAX value, or = to the MIN value, then the set is composed of all equal numbers (nothing would have changed if the stem had said: "the least value is 5, and the mean is 5).
Hope it's sufficiently clear.

if range = 0, it does not mean that SD is necessarily 0.

5 values could be:

5,1,1,1,5 range = 0, but SD is not. 5,5,5,5,5 range = 0, SD = 0.

you're almost right.
In the first case, range is not 0, it is 4. (Max value is 5 and min value is 1)
In this case, range can be 0 only with all 5, as you say in your second example.

Last edited by thearch on 18 May 2005, 07:12, edited 1 time in total.

if range = 0, it does not mean that SD is necessarily 0.

5 values could be:

5,1,1,1,5 range = 0, but SD is not. 5,5,5,5,5 range = 0, SD = 0.

you're almost right. In the first case, range is not 0, it is 4. (Max value is 5 and min value is 1) In this case, range can be 0 only with -5 in the set, since 5 is the max value, or with all 5, as you say in your second example. But sales can't be negative, and the first option (with -5 in the set) is not possible.

I definately agree not only with the answer, but also the approach. nice explanation.

if range = 0, it does not mean that SD is necessarily 0.

5 values could be:

5,1,1,1,5 range = 0, but SD is not. 5,5,5,5,5 range = 0, SD = 0.

you're almost right. In the first case, range is not 0, it is 4. (Max value is 5 and min value is 1) In this case, range can be 0 only with [b]-5 in the set, since 5 is the max value[/b], or with all 5, as you say in your second example. But sales can't be negative, and the first option (with -5 in the set) is not possible.

I definately agree not only with the answer, but also the approach. nice explanation.

but i disagree with thearch's explanation that the range is zero if -5 is in the set. the only possible case to have zero is identical numbers.

if range = 0, it does not mean that SD is necessarily 0.

5 values could be:

5,1,1,1,5 range = 0, but SD is not. 5,5,5,5,5 range = 0, SD = 0.

you're almost right. In the first case, range is not 0, it is 4. (Max value is 5 and min value is 1) In this case, range can be 0 only with [b]-5 in the set, since 5 is the max value[/b], or with all 5, as you say in your second example. But sales can't be negative, and the first option (with -5 in the set) is not possible.

I definately agree not only with the answer, but also the approach. nice explanation.

but i disagree with thearch's explanation that the range is zero if -5 is in the set. the only possible case to have zero is identical numbers.

Yes, you're right of course. I wasn't referring to the -5 part, actually, I glossed over that. I was referring to the fact that you don't need to be able to calculate SD, you just have to know how to use it, and to understand what role range of 0 would have in a SD problem. It definately can come up on the real exam.

if range = 0, it does not mean that SD is necessarily 0.

5 values could be:

5,1,1,1,5 range = 0, but SD is not. 5,5,5,5,5 range = 0, SD = 0.

you're almost right. In the first case, range is not 0, it is 4. (Max value is 5 and min value is 1) In this case, range can be 0 only with [b]-5 in the set, since 5 is the max value[/b], or with all 5, as you say in your second example. But sales can't be negative, and the first option (with -5 in the set) is not possible.

I definately agree not only with the answer, but also the approach. nice explanation.

but i disagree with thearch's explanation that the range is zero if -5 is in the set. the only possible case to have zero is identical numbers.

Oh yes,
you're absolutely right, I think it is better to edit the post and delete such bulls**t

with statement 1 we already ahve the number 5 and we know that the highest value - the lowest is 0. So all number are equals. So deviation =0

with statement 2 we have the information that the mean is 5 but we only know one value for one month (5) so it can be 20,10,5,10,20 or 5,5,5,5,5 for example. Impossible to be sure of the deviation.

with statement 1 we already ahve the number 5 and we know that the highest value - the lowest is 0. So all number are equals. So deviation =0

with statement 2 we have the information that the mean is 5 but we only know one value for one month (5) so it can be 20,10,5,10,20 or 5,5,5,5,5 for example. Impossible to be sure of the deviation.

Hi antmavel,
probably you overlooked that the stem states that "During certain 5 months, the highest month sales value is 5"

with statement 1 we already ahve the number 5 and we know that the highest value - the lowest is 0. So all number are equals. So deviation =0

with statement 2 we have the information that the mean is 5 but we only know one value for one month (5) so it can be 20,10,5,10,20 or 5,5,5,5,5 for example. Impossible to be sure of the deviation.

Hi antmavel, probably you overlooked that the stem states that "During certain 5 months, the highest month sales value is 5"

1) The maimum value is 5 2) the remaining values su = 20 since there are 5 values 3) the only way that the remainng values can be = 20 is 5+5+5+5 since the max value is 5 4) if any one value is less than 5 then the remaining values one of them is greater than 5 example 4 6 5 5 5 -- 6 is not possible

so therefore answer is D

A is also Suff since if in a range al the values are equal only then the SD is 0

Version 8.1 of the WordPress for Android app is now available, with some great enhancements to publishing: background media uploading. Adding images to a post or page? Now...

“Keep your head down, and work hard. Don’t attract any attention. You should be grateful to be here.” Why do we keep quiet? Being an immigrant is a constant...

“Keep your head down, and work hard. Don’t attract any attention. You should be grateful to be here.” Why do we keep quiet? Being an immigrant is a constant...