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==Self-assessment quizzes==
*[https://www.cdc.gov/csels/dsepd/ss1978/index.html CDC Principles of Epidemiology]
*[https://www.med.soton.ac.uk/stats_eLearning/quizzes/index.html Statistics - University of Southampton]
*[https://collegedunia.com/exams/statistics-mcq-mathematics-articleid-4505]
==Types of variable==
flowchart TB
a[Variable]
b[*Quantitative<br>*Numerical] c[*Categorical<br>*Nominal]
d[Continuous]
e[Discrete<br>Integer]
c --- f & g & h
}}
* *Quantitative/numerical variable is also called as '''covariate''' when it is an explanatory (independent) variable
* *Categorical/nominal variable is also called as '''factor''' when it is an explanatory (independent) variable
==Ratio, Rate, Proportion==
a -- ratio of quantity in time-scale ---c[Rate]
}}
==Probability, Likelihood==
--> ''see'' [[Data distribution#Probability, Likelihood|'Probability, Likelihood' in 'Data distribution']]
==Origin of terminology==
===Why is it called "''logistic''"?===
The true reason remains unclear.
The French mathematician who created this term Pierre-François Verhulst first described this word "''logistique''" (Fr.) in his literature in 1845, [https://eudml.org/doc/182533 "Recherches mathématiques sur la loi d'accroissement de la population," in NOUVEAUX MÉMOIRES DE L'ACADÉMIE ROYALE DES SCIENCES ET BELLES-LETTRES DE BRUXELLES, vol. 18, p 3].
In a figure Verhulst described an usual exponential curve as "''logarithmique''", and created a new word "''logistique''" to describe a distinct curve he created by his formula which is now known as a logistic regression formula, but he didn't note through what derivation he created the word.
Description of [https://en.wikipedia.org/wiki/Logistic_function#History Logistic function in Wikipedia is here].
At least, it seems to have nothing to do with a general term "logistics".
===Why is it called "''bootstrapping''"?===
''Bootstrap'' is a piece of cloth or leather at the back or the side of a boot that is used to help you pull it on. A broader meaning is also added the word as an approach to creating something with the minimum amount of possible resources.
There is also an idiom or a template expression of [https://en.wiktionary.org/wiki/pull_oneself_up_by_one%27s_bootstraps ''pull oneself up by one's bootstraps''], which means to improve one's situation on one's own efforts without any other's help.
The method of bootstrapping is to derive new samples from the original observations with replacement, not from other data source, i.e., pulling samples up from themselves, which implies ''pull oneself up by one's bootstraps''.
