During certain 5 months, the highest month sales value is 5. : Quant Question Archive [LOCKED]

MA

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

13 May 2005, 21:23

MA wrote:

A.

thats a blunder. :drunk

thearch

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

14 May 2005, 06:56

Dan wrote:

thearch wrote:

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.

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

14 May 2005, 07:38

thearch,

maybe I am missing something but,

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.

thearch

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

Updated on: 18 May 2005, 07:12

Dan wrote:

thearch,

maybe I am missing something but,

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.

Originally posted by thearch on 14 May 2005, 07:46.
Last edited by thearch on 18 May 2005, 07:12, edited 1 time in total.

ian7777

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

17 May 2005, 12:03

thearch wrote:

Dan wrote:

thearch,

maybe I am missing something but,

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.

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

17 May 2005, 12:17

pb_india wrote:

During certain 5 months, the highest month sales value is 5. What is the deviation of 5 sales values?
1) Range =0
2) Mean=5

'D'

Stmt 1 : Range = 0 -> Std = 0
Stmt 2 = Mean = 5 -> Mean = Highest sales value -> Std = 0

sparky

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

18 May 2005, 02:52

A very nice problem, thanks india_pb

Is 'deviation' a normal name for 'standard deviation'?

HIMALAYA

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

18 May 2005, 06:53

ian7777 wrote:

thearch wrote:

Dan wrote:

thearch,

maybe I am missing something but,

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.

ian7777

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

18 May 2005, 06:57

HIMALAYA wrote:

ian7777 wrote:

thearch wrote:

Dan wrote:

thearch,

maybe I am missing something but,

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.

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

18 May 2005, 07:08

HIMALAYA wrote:

ian7777 wrote:

thearch wrote:

Dan wrote:

thearch,

maybe I am missing something but,

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

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

18 May 2005, 07:42

A for me

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.

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

18 May 2005, 08:06

Antmavel wrote:

A for me

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"

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

19 May 2005, 00:16

thearch wrote:

Antmavel wrote:

A for me

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"

yep
indeed D

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

20 Jun 2010, 00:22

Please read this thread. Some good tips statistics-rules-and-tips-69015.html

B

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

10 Jul 2011, 11:44

This answer has goto be D

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

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Re: During certain 5 months, the highest month sales value is 5. [#permalink]

10 Jul 2011, 11:44