Mathematics - Posts by DNB‭

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Q&A In the Lost Boarding Pass Probability Problem, why couldn't Passengers 2-99 sit in Seats 1 or 100, before Passenger 100 boards?

0 answers · posted 3y ago by DNB‭ · edited 3y ago by DNB‭

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Q&A How can "information about the birth season" bring "at least one is a girl" closer to "a specific one is a girl"?

1 answer · posted 3y ago by DNB‭ · last activity 2y ago by r~~‭

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Q&A Why isn't the probability of being void in 3 specific suits $\frac{1/13}{\dbinom{52}{13}}$?

0 answers · posted 3y ago by DNB‭

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Q&A If Alice must've have classes on at least 2 days, why do you need the intersection of 3 $A_i^C$'s? [closed]

0 answers · posted 3y ago by DNB‭ · edited 2y ago by DNB‭

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Q&A How does the change of variable $\color{red}{r↦n−r}$ transmogrify $\sum\limits_{r=0}^n2^{n-r}\binom{n+r}{n}=2^{2n}$ into $\sum\limits_{k=0}^{n} \frac{\binom{2n-k}{n}}{2^{2n-k}}=1$?

1 answer · posted 3y ago by DNB‭ · edited 3y ago by Moshi‭

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Q&A If A & B are joint, can Arby recoup some of his loss only when $P_{Arby}(A \cup B) < P_{Arby}(A) + P_{Arby}(B)$?

0 answers · posted 3y ago by DNB‭ · edited 2y ago by DNB‭

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Q&A $\sum_{k=0}^{n} \binom{n}{k}=2^{n} \overset{?}{\iff} \sum_{k=0}^{n} \binom{2n+1}{k}=2^{2n}$

1 answer · posted 3y ago by DNB‭ · edited 3y ago by DNB‭

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Q&A Why $\color{red}{k\dbinom{k}{1}} \neq$ "first choose the k team members and then choose one of time to be captain"?

1 answer · posted 3y ago by DNB‭ · edited 2y ago by Wolgwang‭

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Q&A Why shouldn't the Bose-Einstein value be used to calculate birthday probabilities?

0 answers · posted 3y ago by DNB‭

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Q&A You're sampling k people from a population of size n one at a time, with replacement and with equal probabilities. Order or not?

0 answers · posted 3y ago by DNB‭

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Q&A What's the bijection between Stars and Bars and Integer Solutions to an Equality?

0 answers · posted 3y ago by DNB‭

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Q&A Are Stars and Bars in Combinatorics related to the Fence Post Error?

0 answers · posted 3y ago by DNB‭

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Q&A Out of 4 people, why does ways to choose a 2-person committee overcount by 2 the ways to divide the 4 into 2 teams of 2?

1 answer · posted 3y ago by DNB‭ · last activity 2y ago by Tim Pederick‭

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Q&A Explain to a 9 year old — To count each possibility c times, why divide by c? Why not subtract by c?

0 answers · posted 3y ago by DNB‭

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Q&A If k = 1, why $n(n-1) \dots \color{red}{(n-k+1)} = n$?

1 answer · posted 3y ago by DNB‭ · edited 3y ago by DNB‭

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Q&A Intuitively, if you pick k out of n objects singly without replacement, why's the number of possible outcomes NOT $n(n-1) \dots [(n-(k - 1)]\color{red}{(n - k)}$?

1 answer · posted 3y ago by DNB‭ · edited 3y ago by DNB‭

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Q&A Why aren't the "21 possibilities here" NOT equally likely?

1 answer · posted 3y ago by DNB‭ · edited 2y ago by Wolgwang‭

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Q&A Without calculations, how can you visualize "that half the squares are white and half are black"?

1 answer · posted 3y ago by DNB‭ · last activity 2y ago by whybecause‭

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Q&A "A occurred" vs. "something must happen"

1 answer · posted 3y ago by DNB‭ · edited 3y ago by DNB‭

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Meta What story and TWO-digit Natural Numbers best fit Bayes' Theorem chart?

2 answers · posted 3y ago by DNB‭ · last activity 3y ago by Monica Cellio‭

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Q&A What story and two-digit Natural Numbers best fit Bayes' Theorem chart?

0 answers · posted 3y ago by DNB‭ · reopened 3y ago by Monica Cellio‭

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Meta Why isn't \hline rendering here, when it does on Stack Exchange? [duplicate]

0 answers · posted 3y ago by DNB‭ · closed as duplicate 3y ago by Monica Cellio‭

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Q&A What story and one-digit Natural Numbers explain Bayes' Theorem chart most simply?

0 answers · posted 3y ago by DNB‭ · edited 3y ago by Moshi‭

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Q&A How can I deduce which operation removes redundacies?

3 answers · posted 3y ago by DNB‭ · edited 3y ago by DNB‭

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