# APST 207- Final Exam Guide - Comprehensive Notes for the exam ( 36 pages long!)

UNR

APST 207

FINAL EXAM

STUDY GUIDE

Basic Concepts and Measurements

● Statistics are a set of tools and techniques that allow us to collect,organize, and interpret

data and analyze the relationship between pieces of data

○ Numerical Information

What is data?

● Data can be anything

○ Data comprised of variables

● A variable is a characteristic or property we’re interested in

○ If variable is categorical, each answer categories are called classes or levels

■ Variable= gender Classes female/male/other

● Variables describe experimental units (or cases) and vary by experimental units

(individuals, groups, companies, countries)

Variables come in two flavors

● Qualitative variables are not-numerical (they only exist in discrete whole units and result

from descriptions)

○ Dichotomies (Male/Female, Pregnant/Noy

○ Categories ( Race, Class, Eye color)

● Quantitative variables are numerical (they can be order or ranked- obtained by counting

or measuring and are discrete or continuous)

○ Discrete variables: can be assigned values like 1,2,3 4 and are accountable

■ Value is obtained by counting e.g # of students in a class

○ Continuous Variables can assume all values between 2 values

■ Value is obtained by measuring temperature, height, weight

Where do we get data?

● Variables apply to experimental units or cases

● We collect data so we can describe a population

○ The entire set of something = N

● Normally collect samples of a population

○ A subset of a population = n

● EXAMPLE: Population : automobiles with 4 wheels, Samples 20 autos from each maker

Samples

● Representative: exhibiting characteristics typical or desired for the population of interest

● Random every single case in the population had an equal chance (probability of being

chosen

● EXAMPLES :U.S Census, Nation SUrvey of Growth

Two types of statistics

● Descriptive Statistics

○ Only interested in describing a sample or summarizing information about the

sample

○ Measured of central tendency;measures of spread

■ Wealth/Life Expectancy

● Inferential Statistics

○ We want to use the sample to make generalizations about the entire population

○ Estimated of parameters; testing of statistical hypotheses

find more resources at oneclass.com

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■ Influence of temperature on ice cream consumption and crime rates

Our data

● Come in the form of variables

○ That are quantitative or qualitative

● The variables come from experimental units or cases

○ That can be anything we want to observe or ask questions about

● We normally collect a sample of experimental units (cases)

○ States describing just the sample are descriptive

○ Stats that use the sample to tell us something about the population are inferential

Why do we care ?

● The type of variable we have (quantitative or qualitative ) determines the statistic we can

use

○ And how we represent the data

● Population (inferential) and sample (descriptive) statistics are calculated a bit differently

Measurement

● Measurement is the process of assigning numbers and/or values to variables that

describe experimental units (cases)

● Measurement comes in different brands

○ Each one deals with a specific type of data and has its own uses (and pitfalls)

● There are four scales

○ Nominal (qualitative-discrete)

○ Ordinal (quantitative-discrete)

○ Interval (quantitative-continuous)

○ Ratio (quantitative-continuous)

● Discrete - either/or there is nothing “in between” example T-shirt size

● Continuous- exist on a continum

Nominal

● Sometimes are called “categorical” scale

○ Each answer possibility representa a different group or category (only names are

meaningful)

■ May be dichotomous (only 2 classes)

● The answer categories are called classes

○ Exhaustive (account for every possibilty )

○ Mutually exclusive (you can only belong to )

● There is nothing ordered or value-oriented about nominal variables

○ Maybe assigned number values for analysis. Male=0 Female =1

Ordinal

● Rankings: tell you what order your cases come in, but the distance between 1st and 2nd

isn’t clear (adds order to the names)

● EXAMPLE: in race C.J finished 1st, Josh finishes 2nd, and Toby finishes 3rd

○ We know the ranking but not by how much they beat each other.

Interval

find more resources at oneclass.com

find more resources at oneclass.com

## Document Summary

Statistics are a set of tools and techniques that allow us to collect,organize, and interpret data and analyze the relationship between pieces of data. A variable is a characteristic or property we"re interested in. If variable is categorical, each answer categories are called classes or levels. Variables describe experimental units (or cases) and vary by experimental units (individuals, groups, companies, countries) Qualitative variables are not-numerical (they only exist in discrete whole units and result from descriptions) Quantitative variables are numerical (they can be order or ranked- obtained by counting or measuring and are discrete or continuous) Discrete variables: can be assigned values like 1,2,3 4 and are accountable. Value is obtained by counting e. g # of students in a class. Continuous variables can assume all values between 2 values. Value is obtained by measuring temperature, height, weight. Variables apply to experimental units or cases. We collect data so we can describe a population. The entire set of something = n.