#8 - Most people invest in the stock market without doing

[David Boyle]

Hello powerscore,
A quick question with diagraming this one.

Normally the word "without " indicates a necessary condition in which the sufficient condition gets negated .
Here we're not doing that . Is it because it's a "most " statement and that some and most don't get negation or contrapositives,?

Ppl invest -<MOST -> ~ research

Vs
Ppl do not invest <MOST> research


Thanks
John

Hello John,

It is hard to do contrapositives with just "some" or most". If I say, "If I'm happy I eat ice cream", you know for sure that if you didn't eat ice cream, you're not happy. But if there are some possible exceptions, as with "some" or most", then that makes it harder to state firmly that if if you didn't eat ice cream, you're not happy.
As for your diagram, are you trying to do some sort of Mistaken Negation or something? Is that what you meant by "that some and most don't get negation"? Or are you talking about "the sufficient condition gets negated" vis-a-vis "without"-type questions? Clarification could be useful. Thanks!

Hope this helps,
David

[gmosquera42]

Invest in stock market do no research of their own

and

Invest in stock market make a profit

The first Sentence says:

"Most people invest in the stock market WITHOUT doing any research of their own."

Wouldn't that be diagrammed according to the "Unless Equation" as the below?

Not Invested in stock market----> Do research of their own

[Francis O'Rourke]

Hi mosquera,

It is easiest to understand this usage of the word "without" in this sentence as "with no" or "lacking." This is where we can get the statement that stock market investors mostly do no research on their own, or:

Invest in stock market do no research of their own

If you were to apply the Unless Equation to this statement, then you should come up with a slightly different statement than the one you provided. The negation of "most people who invest in the stock market" is "not most people who invest" or "less than the majority of people who invest." This is a valid rephrasing: 'less than the majority of people who invest in the stock market do research on their own' is equivalent to what was provided above. It looks like you provided a polar opposite to "most people who invest" or you overlooked the term "most."

Statements that use "most" or "some" are easy to misinterpret when you stick too closely to the rules of conditional logic. Try to focus on understanding the meaning of the sentence even if you use indicator words like "unless" or "without" to guide your work.

Let me know if this helps!

[disraelyan]

Prep Test 33 December 2000
Q8 - Most people invest in the stock

So general question that arose from this problem that would have caused havoc to me if it was during the real test. I have been under the impression that anytime I see "without" in a conditional statement or premise it acts like a "IF NOT" sufficient statement. So for example the question's first sentence reads..

"Most people invest in the stock market without doing any research of their own."

I would diagrammed this as;

NOT R --MOST-> SM

however the proper way according to a video tutorial is;

SM --MOST-> NOT R

When does "without" act like "unless" or "until" and when are there exceptions like the apparent one above.

[disraelyan]

nevermind was answered had a question about the "without" necessary condition

[madison.lauren]

Wow I am having a hilariously hard time with this question.

I see why A is correct and in fact really wanted to choose that answer but I instead ending up choosing B and I am having a hard time seeing how B can be eliminated.

How I'm conceiving of this is as follows (which I know must somehow be incorrect):

Let's say 60% of investors aren't doing any of their own research and 30% are using brokers and 30% are going off hunches. Most people aren't doing their own research and some are using only one of these two methods. The other groups discussed are at least sometimes doing their own research which excludes them from "most people who invest in the stock market" group.

I recognize that it must be that people other than the two exclusive groups are included in the group discussed in answer B but I don't see how.

Any assistance would be much appreciated!

[Dave Killoran]

Hi Madison,

Lucas made a comment earlier in this thread that might help here. He noted:

• the "these people" refers to the "most people" who invest in the stock market without doing any research of their own. But B splits that group into four categories:
  
  "Some" people who rely solely on their broker's advice
  "Some" people who make decisions merely on hunches
  "Others" (read: some people) who do some research of their own but also often rely on hunches or brokers
  "A few" (also some) who always do research
  
  We have no idea what percentages all these people are.

The key thing is you are always dealing with a subset of the "invest in the stock market" group there, not the whole group. So, when (B) hones in on "Most people who invest in the stock market," it is referring back to the main group, not the subset group of "without doing any research of their own." That opens up the situation and allows for those "other people" you are looking for.

Thanks!