BTGmoderatorDC wrote:Which data set has the greater standard deviation, data set K or data set L?
(1) Every element in data set K is a multiple of 3.
(2) Every element in data set L is a multiple of 9.
Source: Magoosh
\[?\,\,:\,\,\,{\sigma _{\max }}\,\,\left( {K\,\,{\text{or}}\,\,L} \right)\]
\[\left( {1 + 2} \right)\,\,\,\left\{ \begin{gathered}
\,{\text{Take}}\,\,{\text{K}} = \left\{ {0,0} \right\}\,\,\,;\,\,\,L = \left\{ {0,9} \right\}\,\,\,\, \Rightarrow \,\,\,\,? = L \hfill \\
\,{\text{Take}}\,\,{\text{K}} = \left\{ {0,3} \right\}\,\,\,;\,\,\,L = \left\{ {0,0} \right\}\,\,\,\, \Rightarrow \,\,\,\,? = K \hfill \\
\end{gathered} \right.\]
The correct answer is therefore (E).
This solution follows the notations and rationale taught in the GMATH method.
Regards,
Fabio.
POST-MORTEM: in this very special situation, a careful reader may correctly mention that K=L={0} is enough to guarantee the correct answer is (E).
(We don´t want to explain this delicate issue here. We have just mentioned it because our own students will correctly think about that option at once!)
