Elementary Statistics
1-1
A Step by Step Approach
Third Edition
by
Allan G. Bluman
SLIDES PREPARED
BY
LLOYD R. JAISINGH
MOREHEAD STATE UNIVERSITY
MOREHEAD KY
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1-2
Chapter 1
The Nature of Probability
and Statistics
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1-3
Outline
1-1 Introduction
1-2 Descriptive and Inferential
Statistics
1-3 Variables and Types of Data
1-4 Data Collection and
Sampling Techniques
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1-4
Outline
1-5 Computers and Calculators
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1-5
Objectives
Demonstrate knowledge of all
statistical terms.
Differentiate between the two
branches of statistics.
Identify types of data.
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1-6
Objectives
Identify the measurement level
for each variable.
Identify the four basic sampling
techniques.
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1-7
Objectives
Explain the importance of
computers and calculators in
statistics.
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1-8
1-1 Introduction
Statistics consists of conducting
studies to collect, organize,
summarize, analyze, and draw
conclusions.
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1-2 Descriptive and Inferential
1-9
Statistics
Data are the values
(measurements or observations)
that the variables can assume.
Variables whose values are
determined by chance are called
random variables.
variables
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1-2 Descriptive and Inferential
1-10
Statistics
A collection of data values forms
a data set.
Each value in the data set is
called a data value or a datum.
datum
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1-2 Descriptive and Inferential
1-11
Statistics
Descriptive statistics consists of
the collection, organization,
summation, and presentation of
data.
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1-2 Descriptive and Inferential
1-12
Statistics
A population consists of all
subjects (human or otherwise) that
are being studied.
A sample is a subgroup of the
population.
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1-2 Descriptive and Inferential
1-13
Statistics
Inferential statistics consists of
generalizing from samples to
populations, performing
hypothesis testing, determining
relationships among variables, and
making predictions.
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1-3 Variables and Types of Data
Qualitative variables are variables
that can be placed into distinct
categories, according to some
characteristic or attribute. For
example, gender (male or female).
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1-15
1-3 Variables and Types of Data
Quantitative variables are
numerical in nature and can be
ordered or ranked. Example: age
is numerical and the values can be
ranked.
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1-16
1-3 Variables and Types of Data
Discrete variables assume values
that can be counted.
Continuous variables can assume
all values between any two specific
values. They are obtained by
measuring.
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1-3 Variables and Types of Data
The nominal level of measurement
classifies data into mutually
exclusive (nonoverlapping),
exhausting categories in which no
order or ranking can be imposed on
the data.
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1-3 Variables and Types of Data
The ordinal level of measurement
classifies data into categories that
can be ranked; precise differences
between the ranks do not exist.
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1-3 Variables and Types of Data
The interval level of measurement
ranks data; precise differences
between units of measure do exist;
there is no meaningful zero.
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1-20
1-3 Variables and Types of Data
The ratio level of measurement
possesses all the characteristics of
interval measurement, and there
exists a true zero. In addition, true
ratios exist for the same variable.
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1-4 Data Collection and Sampling
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Techniques
Data can be collected in a variety of ways.
One of the most common methods is
through the use of surveys.
Surveys can be done by using a variety of
methods -
Examples are telephone, mail
questionnaires, personal interviews,
surveying records and direct
observations.
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1-4 Data Collection and Sampling
1-22
Techniques
To obtain samples that are unbiased,
statisticians use four methods of
sampling.
Random samples are selected by
using chance methods or random
numbers.
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1-4 Data Collection and Sampling
1-23
Techniques
Systematic samples are obtained by
numbering each value in the
population and then selecting the kth
value.
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1-4 Data Collection and Sampling
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Techniques
Stratified samples are selected by
dividing the population into groups
(strata) according to some
characteristic and then taking
samples from each group.
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1-4 Data Collection and Sampling
1-25
Techniques
Cluster samples are selected by
dividing the population into groups
and then taking samples of the
groups.
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1-5 Computers and Calculators
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Computers and calculators make
numerical computation easier.
Many statistical packages are available.
One example is MINITAB. The TI-83
calculator can also be used to do
statistical calculations.
Data must still be understood and
interpreted.
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