Acceptable Accuracy, Precision, Sensitivity, and Specificity Thresholds
How to know that your machine learning problem is hopeless?
To prove $\left|\frac{p_n(z)}{q_m(z)}\right|\leq \frac{M}{|z|^{m-n}}$ for some $M>0$ How should a GM deal with "standing orders?" Why does $\tan^{-1}(1)+\tan^{-1}(2)+\tan^{-1}(3)=\pi$? Playing around on wolframalpha shows $\tan^{-1}(1)+\tan^{-1}(2)+\tan^{-1}(3)=\pi$. I know $\tan^{-1}(1)=\pi/4$, but how could you compute that $\tan^{-1}(2)+\tan^{-1}(3)=\frac{3}{4}\pi$ to get this result? Close vote review audit is broken - displays "on hold" while reviewing I just reviewed this:    But while reviewing, it already displays the "put on hold as not a real question" section, and it asked:     Should this question be closed as: ?   So as it stands, the audits are broken, since we already know that the question is "on hold" while reviewing, and it is incredibly hard to miss the huge grey box at the bottom.  Another with screenshot: Count number of increasing functions, nondecreasing functions $f: \{1, 2, 3, \ldots, n\} \to \{1, 2, 3, \ldots, m\}$, with $m \geq n$. I stumbled upon a question given like:  Let $m$ and $n$ be two integers such that $m \geq n \geq 1$.   Count the number of functions $$f: \{1, 2, · · · , n\} \to \{1, 2, · · · , m\}$$ of the following two types:  (a) strictly increasing; i.e., whenever $x &lt; y, f(x) &lt; f(y)$, and  (b) non-decreasing; i.e., whenever $x &lt; y, f(x) \leq f(y)$.  I tried in the following way.  For (a). We can say $f(n)&gt;f(n-1)$ AND $f(n)&gt;f(n-2) \ldots f(n)&gt;f(1)$ (total $n-1$ elements)  Similarly for $f(n-1)&gt;f(n-2), f(n-1)&gt;f(n-3) \ldots f(n-1)&gt;f(1)$ (total $n-2$ elements)...  and $f(2)&gt;1$  Like this $$(n-1) + (n-2) + \ldots + (1) = \frac{n(n-1)}{2}$$  Is this correct?  For (b). Since there's equality, it will be $$n + (n-1) + ... (1) = \frac{n(n+1)}{2}$$  Is my approach correct? Any help is appreciated. Thanks in advance. How to easily map c++ enums to strings How to Sort a 2D array? reference variable In some text it is given that we can't assign constant values to a reference variable. When I executed such a program I could do it. Is there any condition we can't assign a constant value to a reference variable? "Its" and "it's" - how to remember? What is a good mnemonic rule that an English learner can use to remember the difference between its (possessive adjective: a team has started its lunch) and it's (verb: it's raining)? Is Switching the Neutral OK? What’s the worst that can happen if i put a switch in the neutral instead of the phase?   I just found out that 3 light bulbs sockets in my home  are connected this way, it first came to my mind to fix it but then I recalled the flow of current from positive to negative is just a convention since the electrons are charged negatively and they actually flow from N to L so i cant really find an solid excuse to mess with the wiring for the next 2 hrs Don't heavier objects actually fall faster because they exert their own gravity? Is there some rare language construct I haven't encountered (like the few I've learned recently, some on Stack Overflow) in C# to get a value representing the current iteration of a foreach loop?  For instance, I currently do something like this depending on the circumstances:  int i = 0; foreach (Object o in collection) {     // ...     i++; } Putting a matrix inside of caption gives \caption has an extra } Why do I have to specify runat="server" on all my ASP.NET controls when it is a mandatory attribute and server is the only option available in my limited knowledge of ASP.NET, and I get an error if I don't use it?  I do understand that I can optionally use it on my HTML tags, and I do understand the client/server paradigm and what it is actually specifying.  Is it a redundant tag that could just be implied by the control being an ASP.NET control, or is there an underlying reason? Is it okay to ask a professor from another university for class lecture notes of a course that he offered on that university? I find two very interesting courses that were offered in the Spring 2019 semester at ETH Zürich. Unfortunately, their class lecture notes are not shared publically. I wonder if it is appropriate to email the professors and ask them for class notes. I just picked up a copy of Windows 7 Pro OEM for install on my computer.  Guy at the store said the only real difference between OEM and standard retail box was tech support.  However, the outside of the box has this big warning that says "The software must be installed with an OPK"?  What is the OPK?  Is it really necessary?  The MS site about it seemed to say it was optional.  EDIT:  BTW - I'm just an individual tinkerer, and not a System Builder Company Employee.  I should have made that clear.  I've used sysprep in a professional setting in the past, so I'm somewhat familiar with its concepts. Word for "someone who talks too much" Is $f(x)=10$ a periodic function? Limit of a particular variety of infinite product/series On which Stack Exchange site can I ask customer service questions about product X or company Y? On which Stack Exchange site can I ask questions like        When will [some new feature] for [some product] be released?   Where can I download an update for [some product]?   I'm getting errors when accessing the customer portal for [some company] – how can I fix this?   Why was I banned for doing [some action] on [some platform]?   Why is [some company] discontinuing [some product]?   Why is [some company] giving away [some product] for free?   What's the price for [some product]?      or any other product support/customer service questions?  It's not a product related to programming (or I've read  on Meta Stack Overflow) so I know Stack Overflow isn't the right place. Which other site in the network will take these kind of questions?