Embed Size (px)
DESCRIPTION
“There are three kinds of lies: lies, damned lies, and statistics.” Mark Twain
Citation preview
Math 205Introduction to Statistical
Methods
Online homework:www.webassign.com
My webpage:people.adams.edu/~rjastalos
“There are three kinds of lies:
lies, damned lies, and statistics.”Mark Twain
How to lie with statisticsDarrell Huff, 1954
How to tell the liars from the statisticians
Robert Hooke, 1983
Book Titles
“You can make statistics show anything!”
On a piece of paper: No names or identifying numbers!
1. height (inches)
On a piece of paper: No names or identifying numbers!
1. height (inches)2. eye color
On a piece of paper: No names or identifying numbers!
1. height (inches)2. eye color3. age
On a piece of paper: No names or identifying numbers!
1. height (inches)2. eye color3. age4. IQ average is 100
Einstein was probably 160 – 170pretty smart ~ 120-130
On a piece of paper: No names or identifying numbers!
1. height (inches)2. eye color3. age4. IQ average is 100
Einstein was probably 160 – 170pretty smart ~ 120-130
5. shoe size
On a piece of paper: No names or identifying numbers!
1. height (inches)2. eye color3. age4. IQ average is 100
Einstein was probably 160 – 170pretty smart ~ 120-130
5. shoe size6. gender
On a piece of paper: No names or identifying numbers!
1. height (inches)2. eye color3. age4. IQ average is 100
Einstein was probably 160 – 170pretty smart ~ 120-130
5. shoe size6. gender7. state of birth (or country, if outside U.S.)
Statistics is the science of collecting, organizing, analyzing, and interpreting data in order to make decisions.
Individuals are the people or objects included in the study
A variable is the characteristic of the individual to be measured
A quantitative variable has a value or numerical measurement for which mathematical operations make sense
A qualitative variable describes an individual by placing the individual into a category or group
Personal Data:
1. height2. eye color3. age4. IQ5. shoe size6. gender7. state of birth
In population data, the variable is measured for every individual of interest
“population” = every individual of interest
In sample data, the variable is measured for only some individuals of interest
“sample” = a subset of the population
A parameter is a numerical description of a population characteristic.
A statistic is a numerical description of a sample characteristic.
parameter population
statistic sample
A statistic is assumedto be an approximation
of a parameter.
Descriptive statistics involves methods of organizing, picturing, and summarizing information from samples or populations
Inferential statistics involves methods of using information from a sample to draw conclusions regarding the population
Probability is a basic tool of inferential statistics.
Nominal level of measurement:• Qualitative only• Categorized using names, labels, or qualities• NO mathematical computations can be made
Nominal level of measurement:• Qualitative only• Categorized using names, labels, or qualities• NO mathematical computations can be made
Ordinal level of measurement:• Qualitative or quantitative• Can be arranged in order• Differences between data entries are not meaningful
Personal Data:
1. height2. eye color3. age4. IQ5. shoe size6. gender7. state of birth
Interval level of measurement:• Quantitative • Can be ordered & subtracted• The zero is arbitrary
Interval level of measurement:• Quantitative • Can be ordered & subtracted• The zero is arbitrary
Ratio level of measurement:• Quantitative, similar to interval data• Can be ordered, subtracted, & divided• Zero really means zero!
Personal Data:
1. height2. eye color3. age4. IQ5. shoe size6. gender7. state of birth
Level of measurement
Put data in categories
Arrange data in order
Subtract data values
Determine if one value is a multiple of another
Nominal Yes No No No
Ordinal Yes Yes No No
Interval Yes Yes Yes No
Ratio Yes Yes Yes Yes
