Do we need parametric tests? First of all, sorry for catchy title, my question is not that broad as it suggests.  I just came to conclusion that I don't need parametric tests. Instead, I need some feedback if my reasoning makes sense. Here it is:  To use some parametric test (like t-test or ANOVA), we have to check assumptions of it (normality, heterogeneity of vaiance). But all the tests for assumptions (Shapiro-Wilk, Kolmogorov-Smirnov, Anderson-Darling, Bartlett, Snedecor's F and so on) test null hypothesis of assumption being met against alternative that it is violated.  So I can only reject null (conclude that assumption is violated) or say that I don't have enough evidence to do that. Typically, in later situation, I use parametric tests. This means that I use it when I do not actually know if assumptions are met.   My conclusion: I should use nonparametric test anyway.  My conclusion 2: I can use parametric test only when I have some "external" knowlegde about assumptions being met (like I somehow know exact distributions of my data).   That's all. I'll be greatful for any suggestions if above makes sense.  Edit: I know that parametric tests are more powerful when their assumptions are met. My concern is that we can never know that this is the case (unless we have "external" knowlegde). So, I think, using parametric tests is pointless since we don't know if we have data appropriate for them.  Analogy that comes to my mind: Imagine two stain removers: Parametric Remover is perfect for cherry juice stains and Nonparametric Remover is OK, but not perferct, for all the stains. Since I can never confirm that my stain is cherry juice, I should always use Nonparameric Remover.
Why would parametric statistics ever be preferred over nonparametric? Can someone explain to me why would anyone choose a parametric over a nonparametric statistical method for hypothesis testing or regression analysis?   In my mind, it's like going for rafting and choosing a non-water resistant watch, because you may not get it wet. Why not use the tool that works on every occasion?
Passing data between view controllers Prove that $\sum_{n=1}^{\infty}\exp\left(-n^{\varepsilon}\right)$ converges. I am an Indian citizen residing in the United States. My wife and I are planning to travel to the UK for a week. We plan to apply for the UK standard visitor visa from the US. I was filling out the application and I have a few questions.   Travel History - The application asks for travel history to the United States, Canada, Australia and New Zealand. Considering that we're resident aliens in the United States, should we consider all the times we've traveled back to the US from India? Travel History - Should we also list out the times we've traveled to India from the US? Cost of the trip - Hypothetically if we plan to spend a total of ~4,000 USD on this trip, should I split up the cost and write down 2,000 USD on my application and 2,000 USD on my wife's application? Income - From what I've read on the forum, my wife must say that "someone else" i.e. me - is paying for her costs and mention my GWF number in the remarks on her application. Would that be sufficient considering that I'll be sending all income documents with my application? Savings - We have joint savings accounts. Should I mention the same amount on both our applications? Posting the documents - Is the up-to-date advice to send all documents in one packet? Or would sending them in separate packets at the same time be better? My thought was to annotate my wife's packet with my GWF number if we were to send them separately. Bank statements - We get e-statements. Would printing those out be enough? I have two partitions that I want to mount on startup: /dev/sda3   /mnt/devel  ext4    defaults    0   2 /dev/sda2   /mnt/excess ntfs    defaults    0   2  The ext4 partition mounts fine (owned by me, writable only by me), but the NTFS mounts owned by root with R\W permission for all. How to fix this? drwxr-xr-x  7 amanda amanda 4096 2012-03-14 19:07 devel drwxrwxrwx  1 root   root   4096 2012-03-14 22:38 excess We have a group of three characters: The lawful good paladin (acolyte), the lawful good fighter (soldier) and the chaotic good druid (criminal). All try to help NPCs in need, won't fight between themselves, but of course have different alignments and personalities. The druid is greedy, but otherwise a good guy. This brought up the question for our group whether greed can be considered a contradiction to having a chaotic good alignment? I understand it as "acting upon what is good, but having your own understanding of 'good'". But I am not sure if the PC being is played 'wrong'.   How do you determine if a given action is in line with a PC's alignment? And should the GM intervene if a PC is played differently that his/her alignment indicates?  Example: There is a Chaotic Good druid with a criminal background. The druid attacked caravans who destroyed his homeland, which he was protecting as his druidic duty, to make way for faster trade routes. Thus he made a name of himself and soon had quite a pile of goods in his territory. The thieves guild caught wind of that and made a deal with him to smuggle wares through his territory as long as they won't hurt the wildlife. So far, seems like a reasonable match between criminal and CG.  Upon opening a chest in a dungeon the druid found a magic chainmail and a bag filled with 420gp. As he was the only one next to the chest, he turned around and told his two comrades there were 360gp in the chest, keeping an extra 60gp to himself without them knowing. Later after finishing a task for the mayor the druid and the paladin persuaded him to give them 550 instead of 500gp, while the fighter was drunk outside. The druid told the paladin to keep his share of those 10% extra, as a gift for always being successful on those charismatic tasks. This was done to check out the personality of the paladin. He accepted without a second of doubt and didn't even contradict when the druid told him not to tell the fighter anything about the extra.   I am now confused about whether this is just unlawful or also not good, and if so what should I as DM do about it? Get the generated SQL statement from a SqlCommand object? I have the following code:  Using cmd As SqlCommand = Connection.CreateCommand     cmd.CommandText = "UPDATE someTable SET Value = @Value"     cmd.CommandText &amp;= " WHERE Id = @Id"     cmd.Parameters.AddWithValue("@Id", 1234)     cmd.Parameters.AddWithValue("@Value", "myValue")     cmd.ExecuteNonQuery End Using   I wonder if there is any way to get the final SQL statment as a String, which should look like this:  UPDATE someTable SET Value = "myValue" WHERE Id = 1234   If anyone wonders why I would do this:   for logging (failed) statements for having the possibility to copy &amp; paste it to the Enterprise Manager for testing purposes Is string in array? What would be the best way to look in a string[] to see if it contains a element. This was my first shot at it. But perhaps there is something that I am overlooking. The array size will be no larger than 200 elements.  bool isStringInArray(string[] strArray, string key) {     for (int i = 0; i &lt;= strArray.Length - 1; i++)         if (strArray[i] == key)             return true;     return false; } Let's say I have a class that has a member called data which is a list.    I want to be able to initialize the class with, for example, a filename (which contains data to initialize the list) or with an actual list.  What's your technique for doing this?  Do you just check the type by looking at __class__?  Is there some trick I might be missing?  I'm used to C++ where overloading by argument type is easy. Prove $\int_0^\infty \frac{\sin^4x}{x^4}dx = \frac{\pi}{3}$ I need to show that  $$ \int_0^\infty \frac{\sin^4x}{x^4}dx = \frac{\pi}{3} $$  I have already derived the result $\int_0^\infty \frac{\sin^2x}{x^2} = \frac{\pi}{2}$ using complex analysis, a result which I am supposed to start from.  Using a change of variable $ x \mapsto 2x $ :  $$ \int_0^\infty \frac{\sin^2(2x)}{x^2}dx = \pi $$  Now using the identity $\sin^2(2x) = 4\sin^2x - 4\sin^4x $, we obtain  $$ \int_0^\infty \frac{\sin^2x - \sin^4x}{x^2}dx = \frac{\pi}{4} $$ $$ \frac{\pi}{2} - \int_0^\infty \frac{\sin^4x}{x^2}dx = \frac{\pi}{4} $$ $$ \int_0^\infty \frac{\sin^4x}{x^2}dx = \frac{\pi}{4} $$  But I am now at a loss as to how to make $x^4$ appear at the denominator.  Any ideas appreciated.  Important: I must start from $ \int_0^\infty \frac{\sin^2x}{x^2}dx $, and use the change of variable and identity mentioned above What are all the correct answers to the Squirrel's questions, and what is the reward when I get them all correct? Non-principal ideal in $K[x,y]$? I see a lot of interesting programs out there that can only be obtained by adding a "PPA" to the system but, if I'm understanding correctly, we should stay within the official "repositories" for adding software to our system.   Is there any way for a novice to know if a "PPA" is safe or if it should be avoided? What tips should the user know about when dealing with a PPA?. Wire transfer to an intermediary bank account I sent money from a bank that doesn't have a space for intermediary bank, so I put the intermediary bank statement information where the beneficiary bank information is supposed to be.  I  don't know what will happen now. Is a quotient group a subgroup? Is a quotient group a subgroup?   I am trying to solve the question below, and if the answer to above is "yes," then my proof will follow below.   I am trying to prove that a cyclic group G, has a cyclic quotient group G/N.  Where N is a normal subgroup.  A SUBGROUP OF A CYCLIC GROUP IS CYCLIC.  By   So if   (1) G is cyclic   (2) G/N is a subgroup   (3) G/N is a cyclic subgroup   (4) The Quotient group G/N is cyclic   I am unsure about my reasoning in step (2), Is this a valid assumption? A tool to measure signal strength of wireless I want to know if there exists any command line option or GUI tool (Ubuntu 11.10) so that I can measure the strength of wireless signal at a given location. I have a house where the wireless is not easily accessible at all corners I want to know at which corners or rooms the signal is weak. Execute shell commands in Python How to plot an emission spectrum? Class method differences in Python: bound, unbound and static What is the difference between the following class methods?  Is it that one is static and the other is not?  class Test(object):   def method_one(self):     print "Called method_one"    def method_two():     print "Called method_two"  a_test = Test() a_test.method_one() a_test.method_two() How and when should I tell my son that his amazing father isn't his biological father? My son is going on 5 and starting to learn a lot about how we're created. I've been with my husband for 10 years, but nearly 6 years ago I had no other choice but to move 1000 miles away and after trying the long distance thing it didn't work so we split up.   I ended up going through a rough patch and started dating an abusive jerk. After a year I was pregnant. He threatened me trying to force me to have an abortion and I refused. His grandmother was chief of police and he scared me into moving back to Florida.  Eventually, when I was 4 months along in my pregnancy my husband and I picked up right where we left off. He loved me so much and accepted our son as if he was his own and has done an amazing job at raising him.   He enrolled in college while I was pregnant, got us a house and went above and beyond to care for us both (as after giving birth I became very ill due to rare brain and spine conditions). I've always tried to do right by my son. Since day one, even while with my husband, I tried to keep the sperm donor involved. But he wanted no part of his son.  My husband stepped up when the biological father refused. The biological father would pretend that he cared, only to tell me he never cared about him anyway and was just trying to manipulate me into stopping child support (which I did anyway after the first year: I felt it wasn't right to take his money when my son had a dad who loved, supported and wanted him from the beginning).  This is a very long story so I'll try and make it not so much of a novel. The sperm donor has made it very clear he wants nothing ever to do with my son. My husband has been Dad since the moment my son entered this world. I've always planned to tell my son as early as possible. I think now, or in a few years, it won't be as hard on him compared to us telling him when he's a teen and who knows how he'd handle it.   I just don't know what to do. We have an extremely happy loving family. My son adores his dad. We never argue, we have a very happy non-dysfunctional marriage. I just feel we have a very special family. But I refuse to lie to my son. What if we wait and someone else maliciously tells him? Or if, when he's older and finds out, he spirals out of control?  I'm so confused, I just want to do the right thing and desperately need advice. Especially from others who have been through similar circumstances. We're planning on meeting with therapists and I guess child development specialists, if someone could also point me in the right direction for what type of doctor is best suited in this situation.   Also my son is very happy. He has a wonderful life and I feel as if he would do fine, knowing how much he loves his dad and just beginning to really grasp the concept of life. I don't think it would change anything for him, if that makes sense. I've been worrying over this for 5 years and really need some answers! Calculus function create Create an example of a function $f: \mathbb{R} \to \mathbb{R}$ such that $f(f(f(\mathbb{R}))) = f(f(\mathbb{R})) \neq f(\mathbb{R})$.