Simpson’s Paradox

Alice and Bob compete. Bob wins convincingly both times. But overall, Alice is better. How come?

This happens for real in medical trials and cases where you don’t have much control over the size of groups you test on:


AliceBob
Trial 1 Score8010
–Out Of /100 /10
––Percentage => 80%=> 100%
Trial 2 Score240
–Out Of /10 /100
––Percentage=> 20%=> 40%
Total Score8250
–Total Trials /110 /110
––Percentage=> 75%=> 45%

The points to notice:

• In each trial, they got different sized groups assigned to them. There can be good reasons for this. One procedure may be known (or thought) to be better for specific circumstances so it would unethical to assign procedure based on “we want to simplify our statistical analysis” rather than on best possible outcome. Or you may simply be combining statistics about things not in your control.

• Alice’s score for her largest group is better than Bob’s score for his largest group, but those ‘largest groups’ were in different trials so they only ever get compared in the overall figure.

More on wikipedia: https://en.wikipedia.org/wiki/Simpson%27s_paradox.

Customise Macos XQuartz : xinitrc doesn’t work

If you installed XQuartz and are, for instance, irritated by the small white xterm window you get, you might try customising it in the usual way by editting an .xinitrc file. If only.

Instead, try this:

defaults read org.macosforge.xquartz.X11

to see all the settings; or to permanently change the startup xterm window, something like:

defaults write org.macosforge.xquartz.X11 app_to_run \
 "/opt/X11/bin/xterm -fa Monaco -fs 12 -fg green -bg black -sb -sl 1000"

Or, if you have installed a better bash with homebrew, then e.g. :

defaults write org.macosforge.xquartz.X11 app_to_run \
  "/opt/X11/bin/xterm -fa Monaco -fs 12 -fg green -bg black -sb -sl 1000 -ls /usr/local/bin/bash"

You can check your syntax before writing the default just by running your quoted command in a terminal, and then watch as XQuartz opens and xterm runs your shell:

~/Source/Repos/VMs] /opt/X11/bin/xterm -fa Monaco -fs 12 -fg green \
    -bg black -sb -sl 1000 -ls /usr/local/bin/bash

To set the default for a new xterm window from the XQuartz Application menu, the menu itself lets you edit the command.

In short, read the FAQ : https://www.xquartz.org/FAQs.html.

Dev Azure Pipeline Web Config Transform

The web.config transform appears at first glance to be somewhat orphaned in Azure DevOps. If you are deploying to a WebApp then the pipeline wizard will probably have given you this snippet for your Build step:

- task: [email protected]
inputs:
solution: '$(solution)'
msbuildArgs: '/p:DeployOnBuild=true /p:WebPublishMethod=Package /p:PackageAsSingleFile=true /p:SkipInvalidConfigurations=true /p:DesktopBuildPackageLocation="$(build.artifactStagingDirectory)\WebApp.zip" /p:DeployIisAppPath="Default Web Site"'
platform: '$(buildPlatform)'
configuration: '$(buildConfiguration)'

To run config transforms you can add the additional parameter /p:TransformConfigFile=true to your msbuildArgs.

The replacement, of course, is the independent FileTransform task (which can also work within zip files). But once your site is packaged the Web.Release.Config is left behind; so you have to run the FileTransform task before, not after, the build step. (Similarly the WebAppDeployment task can’t transform a Web.Release.config that isn’t inside the package).

Slightly magically, the default parameter for the FileTransform is exactly what you typically want for web.Release.config transforms:

#xmlTransformationRules: '-transform **\*.Release.config -xml **\*.config-transform **\*.$(Release.EnvironmentName).config -xml **\*.config' # Optional

FileTransform can also do variable substitution, and you can have multiple FileTransform steps in your pipeline. I also like to see some diagnostic feedback so I include script step to show the xml transform result. But I put it before variable substitution, because the variables often include secrets:

- task: [email protected]
displayName: Transform Release.Config
inputs:
folderPath: '$(System.DefaultWorkingDirectory)/Ui/'
enableXmlTransform: true
xmlTransformationRules: -transform **/*.Release.config -xml **/*.config

- task: [email protected]
displayName: "Confirm web.config transform"
inputs:
targetType: 'inline'
script: 'cat $env:System_DefaultWorkingDirectory/Ui/web.config'
errorActionPreference: 'continue'

- task: [email protected]
displayName: Variable substitution *.config
inputs:
folderPath: '$(System.DefaultWorkingDirectory)/Ui/'
fileType: 'xml'
targetFiles: '**/*.config'

- task: [email protected]
...etc..

Reference