STA 2210 WEEK 2 VOCAB

Statistics

science of analyzing and gathering data

individual data

people or things that are being studied

Variable data

characteristics or values being studied

What are ways to gather data

by counting, measuring, asking questions, surveys, or general observations

Examples of variables

Major, Grade, Points

Examples of individuals

Names of ppl surveyed

categorical variable

labels or descriptions
ex: major or grades

numerical variable

numerical measurements
ex: points

How do you summarize categorical variables?

By using a proportion percent

How do you summarize numerical variables

by using the mean/average

continuous variables

variables that can take on any value in a given data set

discrete variables

variables that can only take on a particular value in a data set

Which describes a discrete variable

a

Which describes a continuous variable

b

Population

All individuals as a group

Sample

smaller group of individuals; a subset of a population

census

getting data from every individual in a population

Parameter

numeric summary that comes from population
population --> parameter

Statistic

numeric summary that comes from a sample
sample--> statistic

Types of Samples

Representative sample, Random sample, Convenience sample

Representative sample

same relevant characteristics as population, not favorable of one group over another

random sample

a sample in which every element in the population has an equal chance of being selected

a random sample is a form of a representative sample

convenience sample

sample where individuals are chosen because they are easy to observe

biased statistical study

design or execution that will favor certain outcomes over others

selection bias

sample method chosen leads to unrepresentable samples of population

What are the two types of statistical studies?

Observational studies and experiments

Observational study

observing or surveying individuals

Experiment

an attempt to influence or change individuals

Subjects

individuals or things we are receiving data from

Explanatory variable (Treatment)

(Independent) variable in the experiment that researchers change, affect, or influence

Response Variable

(Dependent) variable in experiment that is expected to respond to the explanatory variable

Extraneous variables

Variables other than explanatory or response variables that may affect the outcome or response variable
Ex: time, temperature, schedules, etc.

confounding variable

an extraneous variable that does affect the outcome of the experiment/response variable