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August 12, 2020, 11:34:51 am

Author Topic: VCE methods  (Read 106 times)  Share 

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Amith2002

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VCE methods
« on: July 26, 2020, 08:34:21 pm »
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Hey guys!

I'm trying to understand binomial probability and I have a past paper question that i'm trying to answer. The answer is 0.028, I got 0.0243...

The question goes:
In the past, ten percent of people who have been offered a scholarship to complete a particular tertiary course have been male. Of the three scholarships offered this year, what is the probability that less than two were offered to females?

I understand how to get p and n but the only difference is that they got 3C0 and I got 3C1 because they are asking for less than 2.

Help is much appreciated, thanks!

IThinkIFailed

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Re: VCE methods
« Reply #1 on: July 27, 2020, 08:37:19 pm »
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Hey guys!

I'm trying to understand binomial probability and I have a past paper question that i'm trying to answer. The answer is 0.028, I got 0.0243...

The question goes:
In the past, ten percent of people who have been offered a scholarship to complete a particular tertiary course have been male. Of the three scholarships offered this year, what is the probability that less than two were offered to females?

I understand how to get p and n but the only difference is that they got 3C0 and I got 3C1 because they are asking for less than 2.

Help is much appreciated, thanks!

The answer from the exam is right, because less than 2 implies that there are two outcomes that fit with the condition- either no women get the scholarship or 1 woman gets the scholarship.
So when calculating the probability, you should be adding both Pr(X=1) and Pr(X=0) to get the correct probability.

Also, you made a mistake in your calculations for Pr(X=1), because you didnít do the formula correctly- it should be (9/10)^1, not  (9/10)^2. It should also be (1/10)^2 instead.
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