Chapter 1
Introduction To Statistics
I Two Kinds Of Statistics
A. Descriptive Statistics
1. Measures of central tendency
2. Measures of dispersion
3. Measures of association
B. Inferential Statistics
1
II What Are You Expected To Learn?
A. The What, When, and How of Statistics
1. What statistics are available?
2. When each statistic should be used?
3. How each statistic should be computed?
B. Reasons For Studying Statistics
1. Read and understand statistical presentations
in your field
2
2. Design experiments
3. Learn how to use a statistical package to analyze
data
4. Detect fallacies in the presentations of statistical
results
III Describing Characteristics By Numbers
A. Variable: A Symbol That Is Used to Stand
for an Unspecified Element of a Set
1. Range of the variable: set of elements for which
the variable stands
2. Value: an element in the variable’s range
3
B. Classification Of Variables In Mathematics
1. Qualitative variable: range consists of
attributes or non-quantitative characteristics
of people, objects, or events
 Unordered
 Ordered
2. Quantitative variable: range consists of a count or a
numerical measurement of a characteristic
 Discrete
 Continuous
4
C. Measurement in the Behavioral Sciences,
Health Science, and Education
D. Four Levels of Measurement and
Transformations
1. Nominal: one-to-one
2. Ordinal: strictly increasing monotonic
3. Interval: positive linear
X   a  bX , where b  0
4. Ratio: multiplication by a positive constant
X   bX , where b  0
5
E. Importance of Level of Measurement
6