What is Statistics All About, Anyway?Chapter 1: Terminology, Methods, Math

STATISTICS?

Statistics

Statistics

Describe

Graphs Table Number

Infer

Estimate Test

Who do we study? Samples!Who are we interested in? Population!

Who do we study? Samples!Who are we interested in? Population!

Statistic = Measured on the sample

Parameter = characteristic of the population

What do we measure? Variables!

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

MEASUREMENTMajor focus in Research Methods classes.

All research is only as good as its measurement

Measurement 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 do

we use to measure it?

Discrete vs Continuous Variables

COUNTABLE = discrete

FLOWING = continuous

REAL LIMITS

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)

Level (Scale) of Measurement

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

RESEARCH METHODSAll sciences depend on specific analytical methods.Statistics is an integral part of many methods

Correlational MethodsTwo variables are measured to determine the strength and direction of their relationship.

Experimental Method Measure outcomes Apply treatment to one

group, not to another Statistics test whether

the differences between groups could happen by random chance.

Independent and Dependent Variables

Independent variable is manipulated by the experimenter

Dependent variable is the outcome, also called the control condition

Quasi-experiment = groups are not equivalent

MATH NOTATION & REVIEWSee Appendix A for more extensive Math Review.Also “Purple Math” under Stats Success

Summation Notation Omnipresent

Work the TUTORIALS in Aplia to gain efficiency

How does summation fit into the Order of Operations?

Order of Operations

Parentheses Exponents

(powers, roots) Multiplication

or Division SUMMATION Addition or

Subtraction

Statistics as a Second Language

Learn terms best by using them in meaningful work

Practice how to apply definition, not just memorize

Analyze research you learn in other courses

What is Statistics All About, Anyway?Look for as many hidden instances of statistics as you can find before the next class.