Statistics Chapter 1 (Powerpoint)- Sara Langford

What are five ways people gain or maintain knowledge discussed in the lecture?

1. Tenacity

2. Authority

3. Intuition

4. Empiricism

5. Rationalism

What is tenacity?

Holding onto a belief even when contradictory evidence exists.

What is the problem with tenacity?

You do not change your ideas to reflect reality.

What is authority as a way of knowing?

Accepting something as true because a trusted or authoritative source says it is true.

What is the problem with authority?

You may accept information without examining it yourself and continue relying on the source even when the data contradict it.

What is intuition?

Believing something because you feel or "just know" that it is true.

What is the problem with intuition?

It involves little intellectual examination, and many scientific findings are counterintuitive.

What is rationalism?

Gaining knowledge through reasoning.

How does rationalism produce conclusions?

By carefully examining existing knowledge and applying rules of logic.

What is the main weakness of rationalism?

Conclusions may not be verified against the real world.

Why can rationalism limit the discovery of new knowledge?

You start with what you already know and may simply end up verifying what you already believe.

What is empiricism?

Using your senses and observations to learn.

What is the weakness of empiricism?

You can only observe so much, and observations must be interpreted to advance knowledge.

What two approaches does science combine?

Empiricism and rationalism.

How does science combine empiricism and rationalism?

It combines logic with observation to understand the world.

Why is science considered self-correcting?

Logic is used to develop theories, and observations are used to test those theories.

What are the four major purposes of statistical procedures?

1. Organize

2. Summarize

3. Communicate

4. Interpret scores.

What is the goal of scientific research?

To understand the "laws of nature" that apply to the behavior of living organisms.

What is a population?

The entire group to which a law of nature applies.

What is a sample?

A relatively small subset of a population intended to represent the population.

What are participants?

The individuals who are measured in a sample.

What is a statistic?

A number that describes an aspect of the scores in a sample.

What is a parameter?

A number that describes an aspect of the scores in a population.

Statistics describe ______, while parameters describe ______.

Samples; populations.

What type of letters are generally used for parameters?

Greek letters.

What type of letters are generally used for statistics?

English letters.

What is a variable?

Anything that can produce two or more different values when measured.

What are examples of variables?

Age, race, gender, intelligence, and personality type.

What is a relationship between variables?

A change in scores on one variable is accompanied by a consistent change in scores on another variable.

What is a perfectly consistent relationship?

A score on one variable is paired with one and only one score on the other variable.

Does a relationship have to be perfectly consistent?

No. A relationship can exist without perfect consistency.

When does a relationship NOT exist between X and Y?

When the same set of Y scores is paired with every X score.

***A relationship means that when X changes, Y changes in some consistent way too. If changing X does not change what happens with Y, then X gives us no information about Y.***

What are descriptive statistics?

Procedures that organize and summarize sample data.

What are inferential statistics?

Procedures used to draw conclusions about scores and relationships that would be found in the population.

Descriptive statistics focus mainly on what?

The data actually collected from the sample.

Inferential statistics use the sample to learn about what?

The population.

What is a research design?

The way a study is laid out.

What are the two major research designs discussed in the lecture?

Experiments and correlational studies.

What happens in an experiment?

The researcher actively manipulates one variable and measures another variable to see whether a relationship is produced.

What is the independent variable (IV)?

The variable changed or manipulated by the experimenter.

What is a condition in an experiment?

A specific amount or category of the independent variable that creates the situation in which participants are studied.

What is the dependent variable (DV)?

The variable measuring a behavior or attribute expected to be influenced by the independent variable.

Which variable does the researcher manipulate?

The independent variable.

Which variable is expected to be influenced by the independent variable?

The dependent variable.

What happens in a correlational study?

The researcher measures participants on two variables and determines whether a relationship exists.

What is the major procedural difference between an experiment and a correlational study?

An experiment involves actively manipulating a variable; a correlational study measures variables without manipulating them.

What are the four measurement scales?

Nominal, ordinal, interval, and ratio.

What is a nominal scale?

A scale used only to categorize or classify individuals; it does not indicate an amount.

What property does a nominal scale have?

Identity.

Do numbers assigned to nominal categories represent quantities?

No. The numbers are simply category labels.

What is another name for nominal data?

Categorical data.

What is an ordinal scale?

A scale that indicates rank order.

What properties does an ordinal scale have?

Identity and magnitude.

What is the major limitation of an ordinal scale?

You know which score is greater or lower, but not exactly how much greater or lower.

Are the gaps between adjacent ordinal scores necessarily equal?

No.

What is an interval scale?

A scale that represents an actual amount and has equal amounts separating adjacent scores.

Does an interval scale have a true zero?

No.

What is an example of an interval scale?

Temperature.

According to this class, how will Likert scales be treated?

As interval scales.

Why might there be disagreement about Likert scales?

Some consider them ordinal, but most researchers treat them as interval; this class will consider them interval.

What is a ratio scale?

A scale that measures an actual quantity, has equal intervals, and has a true zero.

What does zero mean on a ratio scale?

None of the variable is present.

What is an example of a ratio-scale variable from the lecture?

Reaction time.

What is the key difference between interval and ratio scales?

Ratio scales have a true zero; interval scales do not.

Can any measurement scale also be described as continuous or discrete?

Yes.

What is a continuous scale?

A scale that allows fractional amounts, so decimal values make sense.

What is a discrete scale?

A scale with fixed amounts that cannot be broken into smaller meaningful amounts.

What type of variable is the number of tickets sold to an event?

Ratio and discrete.

What type of variable are soft-drink flavor preferences in the lecture example?

Ordinal and discrete.

What type of variable is weight?

Ratio and continuous.

What type of variable is IQ?

Interval and continuous.