Intro to Stats Flashcards
Why do we study statistics?
To help us develop procedures for evaluating scientific evidence and to evaluate arguments in a responsible manner
What is statistics?
Statistics is a set of procedures and principles for collecting and organizing data and analyzing information in order to help people make decisions when faced with uncertainty. It involves the collection, organization, analysis, and interpretation of data.
There is descriptive and inferential statistics.
Goal of statistics
to take data from a sample and make conclusions about the population.
Purpose of data
to get necessary information and knowledge to make a judgement about a situation.
Descriptive Statistics
Statistics that organize, describe, and summarize a small dataset.
It constitutes the first stage of analysis and is often used when researchers begin a new area of investigation.
Inferential Statistics
Conclusions about populations derived from small (random) samples. Uses a smaller dataset to make estimate and draw conclusions about the greater population.
Can be used to determine cause and effect relationships, test hypothesis, and make predictions.
Variables
Characteristics of a person, object, or phenomenon that is measurable and amenable to change.
Any observable property of organisms, objects, or events.
Can be qualitative or quantitative.
Quantitative Variables
Numerical data that you can add, subtract, multiply, and divide (i.e. age, bmi, blood pressure, exercise in a week, etc.)
They are either continuous (can take on any value within a given range) or discrete (can only take on certain values).
Includes interval and ratio units of measurement.
Qualitative Variables
Data that is categorical. It can be binary, or have more than two categories.
Includes nominal and ordinal units of measurement.
Levels of measurement
(More information conveyed as one moves from A to D):
A). Nominal (categories, not quantified, mutually exclusive. Example is blood type, gender, colour of paint)
B). Ordinal (ranked data. Exampe is letter grades, first, second, third).
C). Interval (equal units of measurement, arbitrary zero point, not proportional. Examples include temperature).
D). Ratio (Zero is absolute, or true, zero represents an absence of the variable, can have direct comparison. Examples include age, distance, weight, time, money).
Dependent Variable
The variable that is measured. A response variable. Measures the effect of the variation of the independent variable.
Independent Variable
The manipulated variable. Its effects on the dependent variable are what we wish to study.
