There are 30 objective questions in an Economics examination paper.
Let X be the number of questions that I scored correct in the paper.
Therefore X~N(30, 0.25)
0.25 is the probability that I will get a question correct.
0.75 is the probability that I will get a question wrong.
If I magically manage to get every single question correct, the probability for that event occuring will be...
P(X=30) = 30C30 (0.25)30 (0.75)0 = 0.00000000000000000086736
Let's say that I know only half of the paper. So, I estimate that I'll get 15 questions correct...
P(X=15) = 30C15 (0.25)15 (0.75)15 = 0.000000000012445
Then let's say that the gods frown on me, and I shockingly end up with not even a single question correct...
P(X=0) = 30C0 (0.25)0 (0.75)30 = 0.00017858
Hence, the probability of me having no questions correct is definitely higher than me mysteriously scoring all questions correct by random choosing.
I'm so doomed in my Economics.
Friday, November 17, 2006
A Bit of Maths...
Posted by Andy at 5:54:00 pm
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4 comments:
No. U would be doom not only for economics but for all the other objective papers if u use probability this way...
given that you actually know how to use your statistics, I bet you'd do fine.
"A bit"?! A BIT?!
*salutes you* Fellow Math nerd! Hahaha.
Really liked your blog...
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