which is a formal logical fallacy known as selection bias.

Haha Jesus Christ...I know the following won’t help you in the slightest. But just in case others are similarly confused:

Formal Logic:

Classical or traditional system of determining the validity or invalidity of a conclusion (inference) deduced from two or more statements (premises)...its focus is not on what is stated (the content) but on the structure (form) of the argument and the validity of the inference drawn from the premises of the argument-if the premises are true then the inference (also called logical consequence) must also be true. The basic principles of formal logic are:

(1) Principle of identity: if a statement is true then it is true.

(2) Principle of excluded middle: a statement is either true or false.

(3) Principle of contradiction: no statement can be both true and false at the same time.

http://www.businessdictionary.com/definition/formal-logic.html

Informal Logic:

is a broad term for any of the various methods of analyzing and evaluating arguments used in everyday life. Informal logic is commonly regarded as an alternative to formal or mathematical logic. Also known as non-formal logic or critical thinking.

In his book The Rise of Informal Logic (1996/2014), Ralph H. Johnson defines informal logic as "a branch of logic whose task it is to develop non-formal standards, criteria, procedures for the analysis, interpretation, evaluation, criticism, and construction of argumentation in everyday discourse.

https://www.thoughtco.com/informal-logic-term-1691169