Is it wrong to standardise a variable (e.g. polygenic risk score) and then centre it for use in multiple regression?
Do you ever center AND standardize variables in multiple regression? It seems as if standardization would automatically center variables...is this true?
In a ring homomorphism we always have $f(1)=1$? How do I install gfortran? I am trying to install gfortran in my computer with Ubuntu 12.04 by using these commands,  sudo -i apt-get update apt-get install gfortran   but I found the program saying "unable to locate package gfortran". Then on a Ubuntu page I found some question regarding the same problem and I went through the solution from them but again I couldn't install the gfortran package.  Can anybody tell me how to install it? Definition of $\mathbb{R}^\infty$ I am trying to check if the user_picture field is empty using the twig template, but I am not able to do this.  I tried lots of ways:-  {% if node.user_picture.value %} {% if node.user_picture.entity %} {% if content.user_picture.value %} {% if content.user_picture|render.entity %} {% if content.user_picture|render %}     Sample of code:    {% if node.user_picture.value %}     &lt;p&gt;User-picture 02&lt;/p&gt;     {{ user_picture }}   {% else %}     &lt;p&gt;Anymonus-picture 02&lt;/p&gt;     &lt;div&gt;       &lt;a href="#"&gt;&lt;img src="{{base_path}}/WEBSITE/themes/THEME/images/anonymous.jpg" alt=""&gt;&lt;/a&gt;     &lt;/div&gt;   {% endif %} How do I delete data for one game in the iPad Game Center? I have one particular game that saves data through the game center. Somehow the saved game data got messed up which causes the game not to work properly when I a connected to the internet (I.e. When the game center is accessible).   Is there some way to delete all the data belonging to that game only? What do Android application permissions mean? When installing an application, the application lists permissions that it needs to perform its  functions.    I am creating this list of the the system defined permissions and a description of what they mean. It is a community wiki so if new permissions are added in the future they can be added to this list. The brightness of my laptop is reset to max on every restart. I tried the solution provided at  but had no luck.   This command   cat /sys/class/backlight/acpi_video0/max_brightness   Returns   cat: /sys/class/backlight/acpi_video0/max_brightness: No such file or directory   Then I found that I don't have a folder named acpi_video0, but a folder called intel_backlight:    Every time I increase or decrease the brightness using the brightness control keys, the values in brightness and actual_brightness get updated.  Is there any method I could follow to set the brightness to a fixed value on every boot and vary it as and when I need it using the brightness control keys? Minipage: 2 tables side by side isn't working I want to show that any two disjoint compact sets in a Hausdorff space $X$ can be separated by disjoint open sets. Can you please let me know if the following is correct? Not for homework, just studying for a midterm. I'm trying to improve my writing too.  My work:  Let $C$,$D$ be disjoint compact sets in a Hausdorff space $X$. Now fix $y \in D$ and for each $x \in C$ we can find (using Hausdorffness) disjoint open sets $U_{x}(y)$ and $V_{x}(y)$ such that $x \in U_{x}(y)$ and $y \in V_{x}(y)$. Now the collection $\{U_{x}: x \in C\}$ covers $C$ so by compactness we can find some natural k such that  $C \subseteq \bigcup_{i=1}^{k} U_{x_{i}}(y)$   Now for simplicity let $U = \bigcup_{i=1}^{k} U_{x_{i}}(y)$, then $C \subseteq U$ and let $W(y) = \bigcap_{i=1}^{k} V_{x_{i}}(y)$. Then $W(y)$ is a neighborhood of $y$ and disjoint from $U$.  Now consider the collection $\{W(y): y \in D\}$, this covers D so by compactness we can find some natural q such that $D \subseteq \bigcup_{j=1}^{q} W_{y_{j}}$.  Finally set $V = \bigcup_{j=1}^{q} W_{y_{j}}$, then $U$ and $V$ are disjoint open sets containing $C$ and $D$ respectively.   What do you think? In cricket how does someone become an umpire at international level? Is there some procedure for this? How are they selected and what is the criteria for this? How do I start skype in the system tray? How can I gear my follower post 2.0? I'm a little confused as to how I'm supposed to gear up my follower since the installation of smart loot in Loot 2.0. My follower still has most pre loot 2.0 items because I have yet to find comparables that are rolling with the right affixes.   To be clear, I play a DH and so I used the Templar as my tank. I very rarely find items that roll with Strength because smart loot sees my DH and rolls Dex for me instead. With the use of the Enchantress I thought it would get better because I could replace Dex with Strength...but that's not true. It seems as though the Enchantress will only roll Dex for me too.   With the auction house down for good, no outlet for trading, and the installation of smart loot, it seems that gearing a follower has become almost impossible unless I want to jump on another character that uses strength and get items that way. I want to find items that I can use while I'm playing. How do I gear my follower post Loot 2.0? Do I have any options other than character jumping? Show that $\langle 2,x \rangle$ is not a principal ideal in $\mathbb Z [x]$ To evaluate limit of sequence $\left(\left( 1 + \frac1n \right) \left( 1 + \frac2n \right)\cdots\left( 1 + \frac nn \right) \right)^{1/n}$ How do I evaluate the limit of the following sequence $$a_n  = \left(\left( 1 + \frac1n \right) \left( 1 + \frac2n \right)\cdots\left( 1 + \frac nn \right) \right)^{1/n}$$   I tried to take log and then using cauchy $1^{st}$ theorem of limits but I coudn't do it.  Could someone kindly help? SQL function as default parameter value? I tried changing a default parameter value with this:  ALTER PROCEDURE [dbo].[my_sp] @currentDate datetime = GETDATE()   and all the SQL pre-compiler gave me was this error:     Msg 102, Level 15, State 1, Procedure my_sp, Line 8 Incorrect syntax near '('.   I have already created the procedure. (I'm not sure if that's relevant.) I was using a null default value and checking for that later, but that doesn't seem proper. Can I do this in one line?   Update: I was going off of :      [ = default ] Is a default value for the parameter. If a default value is defined, the function can be executed without specifying a value for that parameter.            Note:     Default parameter values can be specified for CLR functions except for the varchar(max) and varbinary(max) data types.         When a parameter of the function has a default value, the keyword DEFAULT must be specified when the function is called to retrieve the default value. This behavior is different from using parameters with default values in stored procedures in which omitting the parameter also implies the default value.   Am I reading this wrong?  Many thanks. How do I add a Javascript library to a field formatter? I'm trying to include a Javascript gallery () on my new Drupal 8 site and wrote a field formatter for this purpose.   Now I need to add the jQuery lightGallery to pages using this field formatter and call the library when the page is ready. I am confused about how I am supposed to do this, though.   I defined the library in the module containing my field formatter, but I'm not sure how I attach it only on sites that contain the field.   The documentation of the library uses the jQuery $(document).ready function to call the libary, how would that work inside a Drupal module? How to number and cross-reference \subsubsection-level headers Updating .class file in jar How to use Terminal to delete all .svn folders recursively? What command can I type into the Terminal so that I can delete all .svn folders within a folder (and from all subdirectories) but not delete anything else? PHP variable variables I want to store courseworks marks of n courseworks into n variables, such as cw1 and cw2 etc. Using variable variables how can I come with cw1, cw2 etc.   How can I dynamically create variables?