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bio website gottwurfelt.wordpress.com
location Atlanta, GA
age 30
visits member for 4 years, 4 months
seen 10 hours ago

Data scientist and math blogger.


Mar
22
reviewed Approve suggested edit on derivation of simple linear regression parameters
Mar
19
awarded  combinatorics
Mar
14
comment How likely is it not to be anyone's best friend?
I wonder what, say, Facebook's data on this would look like, where "best friend" would be defined as "person most interacted with on Facebook". Of course this has nothing to do with your model.
Feb
27
reviewed Edit suggested edit on For all sets A, B and C, if $A\setminus(B \cup C) = \emptyset$ ; then $A\setminus C\subseteq B$.
Feb
27
revised For all sets A, B and C, if $A\setminus(B \cup C) = \emptyset$ ; then $A\setminus C\subseteq B$.
improved formatting and changed tags
Feb
18
revised What is my interest rate?
Added new answer
Feb
18
answered What is my interest rate?
Feb
4
comment Expected value of first head in coin toss.
Since $X$ is a discrete random variable, you should take the sum $\sum_x x f_X(x)$, not the integral.
Feb
2
awarded  Nice Answer
Jan
31
comment Inverse birthday estimation
Possible duplicate of math.stackexchange.com/questions/114544/… ?
Jan
31
comment Inverse birthday estimation
Yes, it's natural log. I don't know a name for this problem, although that doesn't mean there isn't one.
Jan
31
answered Inverse birthday estimation
Dec
31
comment What's the name of this quantity?
We have $M_n \ge \lfloor n^2/2 \rfloor$, since $dist(\sigma_n) = \lfloor n^2/2 \rfloor$ when $\sigma_n$ is the ``reverse'' permutation $n(n-1)(n-2) \ldots 1$. This is the sequence oeis.org/A007590. But I can't prove that this is an equality.
Dec
12
comment Proof of inequality with ratio of odds to evens.
This actually may have to do with calculus, depending on what you've learned - take logs of all three members of the inequality and you've converted the problem into showing that a certain sum is between $-\log 2 - \log n$ and $-{1 \over 2} \log 2 - \log n$. If my intuition is right, there are two integrals which are lower and upper bounds for that sum and which have those values. (Comment instead of answer because I haven't worked out the details so I don't know if this works.)
Oct
28
comment Maximum bin load for $\alpha n$ balls into $n$ bins
It would help if you gave a reference to the paper.
Oct
26
awarded  Nice Answer
Oct
24
awarded  Generalist
Oct
4
comment Baseball, batting average, and probability
Sabermetrics folks have already looked into this: see for example here, here, here.
Sep
8
awarded  Good Answer
Aug
31
answered Probability that centre of the square lies inside the circle joining the two points inside the square