Bus Stat Chapter 1

Definitions from Stat chap 1

Statistics

The science of collecting, organizing, presenting, analyzing, and interpreting data to assist in making more effective decisions.

descriptive statistics

Methods of organizing, summarizing, and presenting data in an informative way.

Population

The entire set of individuals or objects of interest or the measurements obtained from all individuals or objects of interest.

Sample

A portion, or part, of the population of interest.

inferential statistics

The methods used to estimate a property of a population on the basis of a sample.

Qualitative variable

a variable that can be qualified or named (car brand, eye color, marital status)

Quantitative variable

a countable variable (years of age, hairs on a head)

Discrete variable

a countable variable with no gaps between variables (cars on a freeway, number of children)

continuous variable

a variable that continues (pie, weight, decimals)

Nominal level of measurement

data recorded at the nominal level of measurement is represented as labels or names. they have no order. they can only be classified and counted

ordinal level of measurement

data recorded at the ordinal level of measurement is based on a relative ranking or rating of items based on a defined attribute or qualitative variable. variables based on this level of measurement are only ranked or counted.

interval level of measurement

for data recorded at the interval level of measurement, the interval or the distance between values is meaningful. the interval level of measurement is based on a scale with a known unit of measurement.

ratio level of measurement

data recorded at the ratio level of measurement are based on scale with a known unit of measurement and a meaningful interpretation of zero on the scale