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#1 2012-09-24 01:00:53
- genericname
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Statistic/Probability - Problems with ''at least'' in it
How do you go about solving problems like this? Is there a trick to it?
A class consists of 25 students, of whom 10 are women and the rest are men. We take a random sample of 5 students from this class. (Without replacement)
-What is the probability that the sample will include at least one woman?
#2 2012-09-24 01:01:54
- bobbym
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Re: Statistic/Probability - Problems with ''at least'' in it
Hi;
You use the hypergeometric distribution.
You will have to sum 5 different terms all involving the hypergeometric distribution. In summation notation it looks like this:
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#3 2012-09-24 02:02:14
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Re: Statistic/Probability - Problems with ''at least'' in it
Is it safe to assume that we use the formula only if it has "at least" in the question?
#4 2012-09-24 02:07:15
- bobbym
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Re: Statistic/Probability - Problems with ''at least'' in it
Hi;
Is it safe to assume that we use the formula only if it has "at least" in the question?
An "at least" in the problem implies a range of values in this case1 to 5. So, you will have to sum 5 hypergeometric terms that is why there is a sum there.
This is the formula:
You could us for say exactly 5 women by saying low = 5 and high = 5. Then you would be summing only one term.
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#5 2012-09-24 08:02:25
- genericname
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Re: Statistic/Probability - Problems with ''at least'' in it
Thank you, Bobby.
#6 2012-09-24 08:05:29
- bobbym
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Re: Statistic/Probability - Problems with ''at least'' in it
Your welcome. May the computing be with you.
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#7 2012-09-24 12:40:01
- genericname
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Re: Statistic/Probability - Problems with ''at least'' in it
Hi, another question:
An instructor gives an exam with 14 questions. Students are allowed to choose any 10 of them to answer. Suppose 6 questions require proof and 8 do not:
-How many groups of 10 questions contain at least one that require a proof?
I got 1736 as an answer. Is that correct?
#8 2012-09-24 16:18:54
- bobbym
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Re: Statistic/Probability - Problems with ''at least'' in it
Hi genericname;
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.