Statistics

Describe

Graphs Table Number

Infer

Estimate Test

Major focus in Research Methods classes. All research is only as good as its measurement

Trait or characteristic

• Possibility of more than one value: it varies

• Values = the possible outcomes of variable

• Measured for each case (individual) in sample

Usually many variables are measured

Independent variable is manipulated by the experimenter.

The control group does not receive the treatment or manipulation.

Dependent variable is the outcome measured by the researcher in each of the groups

Quasi-experiment = groups are not equivalent

Interested in abstract concepts = constructs

• Love, happiness, success, effectiveness

• Depression, risk, poverty, hatred, alienation

• Birth rate, foreclosure rate

Operational definition

• What indicates the presence of love, risk, or success?

• Exactly what procedures dowe use to measure it?

COUNTABLE = discrete

FLOWING = continuous

We assign a number to location on the continuum.

The number is not exact (e.g., 2.4)

Refers to a range of values (here, 2.35 to 2.45)

Yes. Soon we will be computing the Range – the distance from low to high.

We will have to use the Real Limits in the computation, and understand what we did.

Four levels

• Nominal

• Ordinal

• Interval

• Ratio

The statistics wechoose for eachtechnique must be chosen according to the scale of measurement of the variable

Need to recognize it instantly

Continuousvariables are either Interval or Ratio, as they go from low tohigh in equal stepsalong a continuum.

Discrete variables can be found at all levels.

Nominal variables are always discrete.

Ordinal variables are often discrete.

Interval or Ratio variables can be discrete or continuous – need to consider carefully.

Omnipresent in statistics: it is almost all the equations we study.

Need to recognize it as a VERB – it means "Add up"

How does summation fit into the Order of Operations?

Parentheses

Exponents(powers, roots)

Multiplication or Division

SUMMATION

Addition or Subtraction

Learn terms best by using them in meaningful work

Practice how to apply definition, not just memorize

Analyze research you learn in other courses