Module 1

Introduction and Experimental Design Concepts

What are the types of Variables in data?

Categorical and Quantitive

What is the definition of a Categorical variable

Divides the cases into groups/ categories

What is the definition of a Quantitative variable

measure a numerical quantity for each cases

What is the subcategories for Categorical

Nominal and Ordinal

What are the subcategories of quantitative data?

Discrete and Continuous

Define Census

information collected from whole (finite) population

Define Sample Survey

Information collected from a subset of the \n population

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\*\*\*Often use the approach to sampling (and data collection) to distinguish between options...

Why do we want to use Sample Statistics?

to make inferences back about Population Parameters allowing for RANDOMNESS

How do you describe the population

by measuring relationships between variables at a point-in-time (correlations)

What matters most in samples and why?

RANDOM SELECTION! without it, we get biased

What are the variables when it’s a design for an experiment

Treatment variable and outcome variable

What are the \*\*other\*\* variables when it’s a design for an experiment and define it

__**EXPLANATORY VARIABLES**__

attributes we can measure that explain variation in the Outcome

e.g: The Treatment variable is just a ‘special case’ of an \n explanatory variable

\
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__**CONFOUNDING VARIABLES**__

attributes we cannot measure that explain variation in the Outcome

e.g: With COVID-19 this might be attitudes to social distancing, approach to hygiene and isolation, or your job situation

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What are cons in observational studies (rather than experiments)

• Can have SEVERE BIAS due to background effects

• Correlations are not Causation

What are observational studies useful for?

• guiding the development of hypotheses for later experiments

  • We look for evidence of a response in a group getting the treatment BEFORE implementing a large expensive double-blind randomised controlled experiment

• Observational studies are useful for reinforcing the results of double-blind randomised controlled experiments

Define Single-Blind Trials

the participant does not know if they are \n Treatment or Control

Define Double-Blind Trials

neither the administrator of the experiment or the participant knows if they are Treatment or Control