ggarr
Hobbit,
Are Venn Diagrams, Comb/Perms, Standard Deviation and Sequences generally advanced concepts? Aren't there some "simpler" Comb/Perms probs that wouldn't classify as advanced?
Thanks for taking the time to write this.
Venn diagrams raises a need to differentiate tools and tested concepts.... as a tested concept it is certainly advanced one... i'd bet that very few, if any, gmat question really requires the notion of venn diagrams. However (!!!), venn diagram is a strong visualization tool that can help you solving some questions. those question will most probably have another possible approach that wouldn't require it, but some people might find using those diagrams simple.... thus, for those who find those diagrams simple to use - it is not an advanced concept/tool.
Comb/Perm concepts can be tested in many different levels and areas. the basics of Comb/Perm is a must, but only the basics.... the problem with this area is that people (with the encouragement of prep books), tend to overuse formulas and patterns than simple, common sense and cautious counting following the basic principles. also - in order to "practice" their comb/perm skills, people tend to try solving too difficult questions that aren't likely to appear in gmat. not only this makes them feel bad, reducing their confidence, but also shift their focus from required skills for gmat to the required skills of 1st year college course in discrete mathematics.... while this is definitely an interesting course, i fear not many of you would take it willingly and enjoy it like i did.
standard deviation is definitely an advanced concept, rarely asked in gmat. i'd think it is sufficient to know what it is conceptually. no formulas for me (i don't remember them either - and could solve all questions about them here in the forum and on gmat without it).