To find the same standard deviation

gmattesttaker2 wrote:Hello,

Can you please assist with this:

Which of the following sets has the same standard deviation as set {m, n, p, q, r}?

A) {m/2,n/2,p/2,q/2,r/2}
B) { m^2, n^2, p^2, q^2, r^2 }
C) {m + 2, n + 2, p + 2, q + 2, r + 2}
D) {2m,2n,2p,2q,2r}
E) {|m|,|n|,|p|,|q|,|r|}

OA: C


I was wondering when will E be wrong since absolute value will always be positive.

Thanks a lot.

Best Regards,
Sri

Hi Sri,
The Concept behind this question is,
If we add or subtract a constant to each term in a set Mean will increase or decrease by the same constant SD will not change.

Considering the above statement Answer will be C

Coming to you question
Why Not E?
E option will always be Positive, but set {m, n, p, q, r} may have negative values, as
Let set {2,-2,-1,1} wil not have same SD as {2,2,1,1}

Hope I made it clear.

Earlier even I had same confusion. Later Brent and Mitch had explained me clearly.
Here is the link for the same,
https://www.beatthegmat.com/standard-dev ... tml#701110

Regards,
Uva

Uva@90 wrote:

gmattesttaker2 wrote:Hello,

Can you please assist with this:

Which of the following sets has the same standard deviation as set {m, n, p, q, r}?

A) {m/2,n/2,p/2,q/2,r/2}
B) { m^2, n^2, p^2, q^2, r^2 }
C) {m + 2, n + 2, p + 2, q + 2, r + 2}
D) {2m,2n,2p,2q,2r}
E) {|m|,|n|,|p|,|q|,|r|}

OA: C


I was wondering when will E be wrong since absolute value will always be positive.

Thanks a lot.

Best Regards,
Sri

Hi Sri,
The Concept behind this question is,
If we add or subtract a constant to each term in a set Mean will increase or decrease by the same constant SD will not change.

Considering the above statement Answer will be C

Coming to you question
Why Not E?
E option will always be Positive, but set {m, n, p, q, r} may have negative values, as
Let set {2,-2,-1,1} wil not have same SD as {2,2,1,1}

Hope I made it clear.

Earlier even I had same confusion. Later Brent and Mitch had explained me clearly.
Here is the link for the same,
https://www.beatthegmat.com/standard-dev ... tml#701110

Regards,
Uva

Hello Uva,

Thank you very much for the explanation and for sharing the link.

Best Regards,
Sri

Uva@90 wrote:

gmattesttaker2 wrote:Hello,

Can you please assist with this:

Which of the following sets has the same standard deviation as set {m, n, p, q, r}?

A) {m/2,n/2,p/2,q/2,r/2}
B) { m^2, n^2, p^2, q^2, r^2 }
C) {m + 2, n + 2, p + 2, q + 2, r + 2}
D) {2m,2n,2p,2q,2r}
E) {|m|,|n|,|p|,|q|,|r|}

OA: C


I was wondering when will E be wrong since absolute value will always be positive.

Thanks a lot.

Best Regards,
Sri

Hi Sri,
The Concept behind this question is,
If we add or subtract a constant to each term in a set Mean will increase or decrease by the same constant SD will not change.

Considering the above statement Answer will be C

Coming to you question
Why Not E?
E option will always be Positive, but set {m, n, p, q, r} may have negative values, as
Let set {2,-2,-1,1} wil not have same SD as {2,2,1,1}

Hope I made it clear.

Earlier even I had same confusion. Later Brent and Mitch had explained me clearly.
Here is the link for the same,
https://www.beatthegmat.com/standard-dev ... tml#701110

Regards,
Uva

Hello Uva,

Thank you very much for the explanation and for sharing the link.

Best Regards,
Sri