Chapter 1 - What is Statistics? Flashcards
Why do we study statistics?
- numerical information is everything
- statistical techniques are used in decisions
- help make educated decisions
What is Statistics?
The science of; collecting, organizing, presenting, analyzing, and interpreting data to assist decision making
Types of Statistics
Descriptive
Inferential
Population
Sample
Descriptive
Methods of organizing, summarizing, and presenting data in an informative way.
Inferential
Methods used to estimate property of a population, based on sample.
Population
The entire set of individuals or objects of interest or the measurements obtained from all objects/individuals of interest.
Sample
A portion, or part, of the population of interest.
Types of Variables
Qualitative/Attribute
Quantitative
Qualitative/Attribute
Characteristics being studied are nonnumeric
Ex. A classification of students in your university by the province of birth, gender ect.
Quantitative
Information is reported numerically
Ex. Balance in checking account
Types of Quantitative Variables
Discrete
Continuous
Discrete
can only assume certain values and there are usually “gaps” between values.
Ex. The number of bedrooms in a house
Continuous
Can assume any values within a specific range
Ex. The weight of a pork chop
The 4 levels of measurement
Nominal
Ordinal
Interval
Ratio
Ratio
Level of measurement in which observations of a qualitative variable can only be classified and counted
Ex. eye colour, gender
Ordinal
Data arranged in some order, but differences between data values cannot be determined.
Ex. Students can rate a professor on a scale of: Poor, fair, average, good, excellent
Interval
Ranking of characteristics of the ordinal level and in addition the difference between the values is a constant size.
Ex. Temperature, shoe size.
Ratio
All characteristics of the interval level, in addition, the zero point is meaningful and the ratio between two numbers is meaningful.
Ex. Monthly income of surgeons
