Unit 1: Introduction

Outline

1.1       Definition

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

1.2       Groups

 •   A Population includes all members of a group.•   A Sample is selected members that (hopefully) represent the Population.•   A Parameter is a measurement of the Population, which•   A Statistic is a measurement of the Sample.

1.3       Scales of Measurement

 •   Nominal: Categories•   Ordinal: Categories with order•   Interval: Numbers with equal distance between points•   Ratio: Numbers with equal distance between points and a meaningful zero.
 • 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

Study
Guide