## O_Ojereisha 3 years ago Consider the following situation and explain what might be a problem with the credibility of the source or the thinking involved: You got your essay back in English class and you received a "B" on it. The girl sitting behind you, a friend of yours, also received a "B" and her boyfriend, who is another period class with the same teacher and the same subject, also received a "B." You concluded then that no one that wrote that particular assignment for that particular teacher received an "A." Pitfalls in credibility? help please

1. geoffb

That swan is white. Therefore, all swans are white. What do you think is wrong with that statement?

2. O_Ojereisha

not all swans are white?

3. geoffb

Potentially. But in terms of the actual statement, can you determine what's wrong? Is it a fair conclusion for me to form?

4. O_Ojereisha

No?

5. geoffb

Okay, why not?

6. geoffb

If I've only ever seen one swan, and it was white, it is scientifically "true" that all swans are white. But what is the caveat?

7. O_Ojereisha

i don't understand

8. geoffb

If I get a \$5 bill and it is ripped, I might say all money is ripped. Let's say the next bill I get is also ripped. That continues to support my theory. But what is the problem? Is it fair for me to extrapolate that to all bills? (Hint: No.) Why not?

9. O_Ojereisha

because you only gooten two ripped bills?

10. geoffb

Right. All it will take is one bill that isn't ripped to disprove my theory. Just as it only takes one black swan to disprove my theory that all swans are white. That is what science is all about. Theories exist until they no longer work. Many theories, like the law of gravity, have been observed so much that they are taken to be self-evident. (But keep in mind that it would only take one instance of no gravity (and I don't mean like in space—there is still gravity) to disprove the theory. So, back to your original question. What is the problem with the "experiment?"

11. O_Ojereisha

it will only take one person to get an A to disprove there theory?

12. geoffb

Exactly! How many people did "you" ask, and how many people do you think are in the two classes (don't need an actual number—just think about it relatively). Is it fair to base your assumption on such a sample size?

13. O_Ojereisha

no

14. geoffb

Okay, why not?

15. O_Ojereisha

because it was only 3 people who she knows got an B

16. geoffb

Exactly! There are dozens of potential classmates she didn't ask, so it's not a fair conclusion to make when she only asked 3 (one being herself).

17. O_Ojereisha

Thanks!!!

18. geoffb

No problem. So, it's not so much an issue of credibility (you can assume your friend and her boyfriend told you the truth), but certainly a problem with the thinking involved. This is an inference based on too little evidence. (Though, if you don't understand what an inference is, I wouldn't use it in your answer. ;) Good for you for working through the problem. Nice to see.