1,210 reputation
216
bio website andrew-christianson.github.io
location Los Angeles, CA
age 23
visits member for 2 years, 10 months
seen 16 hours ago

Dec
11
suggested suggested edit on Running times comparison
Dec
11
answered Calculating position along the hypotenuse
Dec
11
revised How can I find the square root using pen and paper?
edited body
Dec
11
answered How can I find the square root using pen and paper?
Dec
10
answered Probability cut-off
Dec
10
comment Probability cut-off
I'm curious as to the context of your question. A brief foray into google seems to indicate that 'Event Rate' is associated with biostatistics/Evidence-Based Medicine. So, what context is this in?
Dec
7
comment Ranking a set – is pair-based voting a good idea?
My voting theory professor was fond of illustrating that, holding the preferences a population of voters constant, one could make successive pairwise votes favor any option by the introduction of specific polarizing options and careful ordering of votes. Thus, I'm inclined to say that the efficacy of ranking by pairs depends somewhat strongly on your set and choice of voting procedure. If you're ranking a large set and pairwise elections are random and repeated, I think it's not an terrible system. Could you expand upon the nature of the problem a bit?
Dec
7
comment Simple probability problems
@norbert if you really want to stick with the unordered view, you have to use the probabilities at the end of Dilip's comment. There are 3 equally likely unordered pairs that sum to 7: (1,6),(2,7),(3,4) each with a probability of $\frac{2}{36}$. So, we sum the probabilities of those pairs and get a total probability of $\frac{6}{36} = \frac{1}{6}$
Dec
7
comment Simple probability problems
@norbert to roll two dice. Consider: rolling a pair of dice and totaling the scores should be completely identical to roll one die twice in succession and taking the total of the two rolls. In the latter case, I think you would agree that rolling a 4, then a 3 is not the same as rolling a 3, then a 4. Precisely the same process is at work in the former case, so we count the sample space in the same way.
Dec
7
comment Simple probability problems
@norbert You can't just reject the assumptions of the model you're using to calculate the probability and expect it to provide good results. Consider your first problem - the black balls are indistinguishable from each other, but, when calculating the probability of drawing one, it would be incorrect to state that, since one cannot tell them (or their white counterparts apart) then there is only $\binom{2}{1}$ ways to pick one ball. In the same way, while it's clear that (3,4) and (4,3) are effectively the same roll, they are distinct for the purposes of calculating the total number of ways
Dec
7
comment Simple probability problems
Sorry about that, it checked out in the preview but apparently the full MathJax doesn't like mismatched $$ and $
Dec
7
revised Simple probability problems
added 1 characters in body
Dec
7
answered Simple probability problems
Dec
6
comment Breaking the mental block of an area of Mathematics?
Which text(s) are you using in the course sand in your own studies?
Dec
5
revised indicator variable are uncorrelated, if they are independent?
rewrote to put implications in the standard order (if->then). If this isn't ok, sorry, feel free to reject.
Dec
5
suggested suggested edit on indicator variable are uncorrelated, if they are independent?
Dec
5
answered Completing the square
Dec
4
comment Completing the square
So, the first equation is equal to (A^2 +B^2+C^2) and the second to the multiple of it? And are you allowed matrix algebra to solve systems of linear equations?
Dec
4
comment Geometric series
Additionally, what is the context of this problem? It looks closest to finding the PV of a growing annunity, but its not exactly the same.
Dec
4
comment Geometric series
@james $r=\frac{v}{1.05}$ in dls's answer is $\frac{1}{1.05^2}$ as well.