Data Analysis

The information we can obtain from analysing data depends on how that data was obtained.
There are two ways of gathering data: observational studies, and experiments.
In observational studies, individuals and their properties are observed without being affected in any way by the study.
Experiments on the other hand, are studies that deliberately influence individuals in order to see how they respond. Variables are changed to see how other variables are affected.

Data Analysis Terms
Population - Any group of individuals we are interested in, e.g. oranges, students,dogs, etc.

Sample – A small proportion of individuals from a population which are used to estimate properties of that population..
Probability Sample (also Random Sample) – A sample for which individuals are selected from a population by a method based on chance.
Simple Random Sample (SRS) – An SRS is a type of probability sample for which individuals are chosen completely at random from a population

Parameter - A number that describes a property of a population.

Statistic - A number that describes a property of a sample.

Confounding – When the effects of an explanatory variable on a response variable cannot be distinguished from the effects of lurking variables on that response variable. In other words: when we cant tell if it’s our explanatory variable, or a lurking variable, that’s affecting the response variable.

Bias – When a study is designed in a way that favors certain results. For example, if you did a study to find out the most popular sport, but only interviewed tennis players.