## Psych 2: Unit 1

## Unit 1: Introduction

Outline

1.1 Definition

• is the Science of Data.Statistics• summarize and describe data.Descriptive Statistics • enable us to make conclusions and decisions about data.Inferential Statistics |

1.2 Groups

• A includes Population• A all members of a group.is selected members that (hopefully) represent the Population.Sample • A is a measurement of the Parameteropulation, whichP• A is a measurement of the Statistic ample.S |

1.3 Scales of Measurement

• : CategoriesNominal• : Categories with orderOrdinal• : Numbers with equal distance between pointsInterval• : Numbers with equal distance between points and a meaningful zero.Ratio |

• Use 7 to 15 rows, with consistent interval width. • x is observations, f is frequency, cf is cumulative frequency, % is percentage, cum% is cumulative percentage.• Sort scores or score intervals from high to low. • Calculate cf from the bottom – up.• % = f divided by total.• cum% = cf divided by total• First row of cf should equal the total number of observations. • First row of cum% should be exactly 100%.• The lowest and highest score or score interval must have a frequency other than zero. • All possible scores or score intervals between the lowest and highest must be reported. (How to by DataScienceCentral) |

1.5 Algebra Review

• Order of Operation • Rounding Off |