Venn Diagram Help: Step-by-Step Guide for Test Preparation | ItsAllGood

In summary, the conversation is about finding the probability of being within either A or not-B (or both) based on a given diagram. The universe is represented by 100 and the numbers and corresponding areas on the diagram add to 50. To solve, one must add up all things that are not in B and those that are in both A and B. The correct answer is D>42.
  • #1
kray
2
0
Hi everyone, I've got a test tomorrow, and I've no idea how to do this question;

http://server5.uploadit.org/files/itsallgood-help.JPG [Broken]

If someone could please do a step by step guide how to do this, it would be great.


Thanks very much. :smile:
 
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  • #2
My first question is: do you know what those symbols mean? I'll translate: find the probability of being within either A or not-B (or both).

Then realize that the three numbers (and corresponding areas on the diagram) represent the entire universe: they add to 50. So... what's in A? what's not in B (that's not-B)? What's in either A or not-B? Get it?

Edit: I misread the diagram: the number 50 in the diagram represents the area outside of the overlapping ovals. Thus the universe = 50 + 50 = 100.
 
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  • #3
I believe there's an additional 50 outside the sets A and B. So n(U) = 100. N(A) = 28. n(-A ^ -B) = 50. So that gives you one of the specified answers.
 
  • #4
Cheers guys,

I understand what the symbols mean, i just cannot understand how this has been done.

p.s the answer comes out to D> 42

I've tried for hours, and nothing i know gets this answer.


A misprint maybe? :tongue2:
 
  • #5
kray said:
p.s the answer comes out to D> 42
It's no misprint. (You mean 42/50, I presume.)

I goofed before. Gokul43201 is correct: that 50 refers to the area outside the overlapping ovals. Thus the total universe is 100, not 50. (Shame on me. :uhh: )

The way to solve these things is to take a pencil and mark every section of the diagram that meets the criteria. Then just add the numbers. Start with everything that is not-B.
 
  • #6
However, Gokul43201's answer is incorrect. D is, in fact, the correct answer.

As Doc Al said, Add up all things that are not in B (that are not B), then add those that happen to be in both A and B. (Hint: there is a single number in your picture that gives all things that are NOT in "A or not B"- you can just subtract that from 100 to get the number you want). Since the universe is 100, divide by 100. You will need to reduce the fraction to get the answer given.
 

1. What is a Venn diagram?

A Venn diagram is a visual representation of the relationships between different sets of data or objects. It is made up of overlapping circles that show the similarities and differences between the sets.

2. How do I create a Venn diagram?

To create a Venn diagram, you will need to first determine the sets or categories you want to compare. Then, draw overlapping circles to represent each set and label them accordingly. Finally, fill in the overlapping areas with the common elements or characteristics shared by the sets.

3. What is the purpose of a Venn diagram?

The purpose of a Venn diagram is to help organize and analyze data by visually representing the relationships between different sets. It can also be used to identify similarities and differences between sets to better understand the data.

4. Can a Venn diagram have more than three circles?

Yes, a Venn diagram can have any number of circles as long as they overlap in some way. However, the more circles there are, the more complex the relationships between the sets become, making it more difficult to interpret the data.

5. How is a Venn diagram different from a Euler diagram?

A Venn diagram uses overlapping circles to represent the relationships between sets, while a Euler diagram uses non-overlapping shapes such as circles, ellipses, or rectangles. Additionally, a Venn diagram can only show relationships between two or three sets, while a Euler diagram can show relationships between any number of sets.

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