In this post I am going to explain how to enable GUI root access on Debian 9. Instructions for Debian 10 are similar and can be found here. At this point I should warn you that using the root account is dangerous as you can ruin your whole system. Try to follow this guide exactly.

# Category Archives: Computing and Others

# Seasonal adjustment

# What is seasonal adjustment?

Seasonal adjustment refers to a statistical technique that tries to quantify and remove the influences of predictable seasonal patterns to reveal nonseasonal changes in data that would otherwise be overshadowed by the seasonal differences. Seasonal adjustments provide a Continue reading Seasonal adjustment

# Clustered Standard Errors in R

The easiest way to compute clustered standard errors in R is the modified ` summary()`

. I added an additional parameter, called `cluster,`

to the conventional ` summary() `

function. This parameter allows to specify a variable that defines the group / cluster in your data. The summary output will return clustered standard errors. Here is the syntax:

` summary(lm.object, cluster=c("variable")) `

Continue reading Clustered Standard Errors in R

# Example data – Clustered Standard Errors

The following R script creates an example dataset to illustrate the application of clustered standard errors. You can download the dataset here.

The script creates a dataset with a specific number of student test results. Individual students are identified via the variable ` student_id `

. The variable ` id_score `

comprises a student’s test score. In the test, students can score from 1 to 10 with 10 being the highest score possible. Continue reading Example data – Clustered Standard Errors

# Robust Standard Errors in STATA

”Robust” standard errors is a technique to obtain unbiased standard errors of OLS coefficients under heteroscedasticity. In contrary to other statistical software, such as R for instance, it is rather simple to calculate robust standard errors in STATA. All you need to is add the option ` robust `

to you regression command. That is:

# Robust Standard Errors in R

One can calculate robust standard errors in R in various ways. However, one can easily reach its limit when calculating robust standard errors in R, especially when you are new in R. It always bordered me that you can calculate robust standard errors so easily in STATA, but you needed ten lines of code to compute robust standard errors in R. I decided to solve the problem myself and modified the ` summary() `

function in R so that it replicates the simple way of STATA. I added the parameter ` robust `

to the ` summary() `

function that calculates robust standard errors if one sets the parameter to true. With the new ` summary() `

function you can get robust standard errors in your usual ` summary() `

output. All you need to do is to set the ` robust `

parameter to true:

` summary(lm.object, robust=T) `

Continue reading Robust Standard Errors in R

# Robust Standard Errors in R – Function

One can calculate robust standard errors easily in STATA. However, one can easily reach its limit when calculating robust standard errors in R. Although there exist several possibilities to calculate heteroscedasticity consistent standard errors most of them are not easy to implement, especially for beginners. I modified the ` summary() `

function in R so that it replicates the simple way of STATA. You can find the new ` summary() `

function below. Furthermore, I uploaded the function to a github.com repository. This makes it easy to load the function into your R session. In order to see how you can import the new ` summary() `

function into your R session and how you can use it see this post here. Continue reading Robust Standard Errors in R – Function

# Self-Hosted WordPress Permalink Problems – Solve Database Issues

Finally, if you are still here it means that you properly applied point 1 to 3 of the checklist and you are still experiencing problems with permalink.

I have one last point that you should check out. Sometimes WordPress does not Continue reading Self-Hosted WordPress Permalink Problems – Solve Database Issues

# Self-Hosted WordPress Permalink Problems – set AllowOverride all

WordPress uses .htaccess to manipulate how Apache serves files from its root directory, and subdirectories thereof. Most notably, WP modifies this file to be able to handle pretty permalinks. However, Apache must allow the use of .htaccess files in order for WordPress to use the file. Set the parameter ”AllowOverwrite” of the file ”apache2.conf” file to ”All” in order to tell Apache to allow the use of .htaccess files. Continue reading Self-Hosted WordPress Permalink Problems – set AllowOverride all

# Self-Hosted WordPress Permalink Problems – .htaccess permissions

In case you .htaccess exists and is placed in the right directory you should check if it has the right permissions and if the right user owns it. The right user should be your linux user handling WordPress. On Debian (it will be similar on other systems, I suppose) you can find the owner and the permission of a file or directory with the command ` ls -l /path/to/directory`

. The output will tell you the permission on the file (”-rw-r–r–” in my case) and who owns the file (”www-data” in my example). The second ”www-data” indicates the group, which is identical than the owner in my case. Continue reading Self-Hosted WordPress Permalink Problems – .htaccess permissions