SHARON LAWNER WEINBERG
SARAH KNAPP ABRAMOWITZ
Bivariate
Relationships
Chapter 5
Statistic
Usin
s
g
SPSS
An Integrative Approach
SECOND EDITION
Summarizing the Relationship Between
Two Variables: An Overview
Variable Types
Summary Graphic
Summary Statistic
The http:/tpj.sagepub.com/
Prison Journal
A Large-Scale Multidimensional Test of the Effect of Prison
Education Programs on Offenders' Behavior
KENNETH ADAMS, KATHERINE J. BENNETT, TIMOTHY J. FLANAGAN,
JAMES W. MARQUART, STEVEN J. CUVELIER, ERIC FRITSCH,
Degrees of Freedom explained
The degrees of freedom of a set of observations are the number of values which could be assigned
arbitrarily within the specification of the system. Statisticians use the terms "degrees of freedom" to
describe the number of va
Sally Lam
27 October 2008
Hypothesis testing is an inferential/ statistical procedure that uses
sample data to draw a general conclusion about a population
It involves a set of logical procedures and rules that enable us to make
general statements/ infere
There are three different types of t-test
1. One-sample t-test
2. Independent-samples t-test
3. Paired-samples t-test
The type of t-test you use is determined by the research
design employed
2
1. One-sample t-test
Compare a single sample mean with a kn
TESTING DIFFERENCES
BETWEEN MEANS
STA 250
These slides include the calculation of
the t statistic and instructions for all
three types of t tests in SPSS / PSPP.
REVIEW
Hypotheses Testing:
Statistical Hypotheses:
Null Hypothesis
Alternative (Research)
Guided Lecture 6 Sampling Distributions
Why do we need to use samples in research?
An issue of great concern in criminology is the appropriate sanction for acts of serious offending by
youth between 12 and 16. What can we do in response to a nasty robbery
Moving from Descriptive to Inferential Statistics
Everyone wants to be able to generalize from their observations: after you have the same experience in
the similar conditions a few times, you begin to expect the same result when you find yourself in thos
We have discussed the Z-score, normal distribution (normal curve),
probabilities, and Unit Normal Table
If the distribution or variable is normal, you should be able to
determine the probability value for obtaining any individual (raw)
score from the pop
Probability & Sampling REVIEW of basic terms & concepts
Key Concepts and Terms
Empirical distribution the distribution of frequencies of values of a known (observed) variable.
Example: Frequency distribution of prisoners by gender in a sample of data
Empi
Practice Problems Area and Z scores
Find the area under the normal curve that lies between the following pairs of z-values. (Give your
answers correct to four decimal places.)
(a)
z = 0 to z = 1.60
(b)
z = 0 to z = 1.14
(c)
z = 0 to z = 2.85
(d)
z = 0 to
Percent and Proportions
PERCENTAGES
Definition: A "percent" or "percentage" is a part, portion, or proportion of something that can be
counted.
CRJ Use: We use percentages to compare the proportion of crime that is represented by different
crime types. Fo
Guided Lecture 4 Relationships between Two Variables
After gaining a basis in the ways to explore a single variable its shape, center and variability the next
step is to consider how two variables may be related. This is a basic step in research: to pose
SHARON LAWNER WEINBERG
SARAH KNAPP ABRAMOWITZ
Measures of a
Distributions Central
Tendency, Spread, and
Shape 3
Chapter
Statistic
Usin
s
g
SPSS
An Integrative Approach
SECOND EDITION
Overview
Measures of Central Tendency (Level)
Mode
Median
Mean
Meas
Chebyshevs Theorem
For any number k (such as 2 or 3) that is greater than 1, at least 1-1/k2 of the data
will fall within k standard deviations of the mean.
This theorem can be applied to any distribution.
So, for example, the amount of data that will fal