Chapter 1 Vocabulary

statistics

the science of conducting studies to collect, organize, summarize, analyze and draw conclusions from data.

variable

characteristic or attribute that can assume different variables

data

values that a variable can assume

population

all subjects that are studied

sample

a subset of a population

descriptive statistics

collection, organization, summarization, and presentation of data.

inferential statistics

generalizing from samples to populations, performing estimations and hypothesis tests, determining relationships among variables, and making predictions.

qualitative

categorical data.

quantitative

numerical data.

discrete

data that is countable. 1,2,3...

continuous

data that is not countable and can be decimals. 4.26, 8.43...

nominal level of measurement

the lowest level. unranked categories

ordinal level of measurement

2nd level. ranked categories.

interval level of measurement

3rd level. ranked categories with consistent intervals

ratio level of measurement

Highest level. Ranked categories with consistent intervals and a true zero.

random sample

sample chosen completely at random. Random number generator, choosing numbers out of a hat.

systematic sample

choosing every kth value in a population

stratified.

Grouping population into groups with like characteristics, then choosing random samples from each group.

cluster

A population already split into natural groups. Sampler chooses full groups as sample.

observation study

Researcher does not manipulate anything in the study. Merely observes in a natural setting.

experimental study

Researcher manipulates a treatment group in order to compare results with the non-manipulated control group.

independent variable.

The variable a researcher manipulates. On the x axis.

dependent variable

The outcome variable that the researcher does not manipulate. On the y axis.

confounding variable

Manipulates the outcome of the experiment without being accounted for in the independent variable.