A-1
Appendix A Statistics in Psychology A-
Why study statistics?
Psychology is a science, and scientists must have ways of describing, summarizing, and
analyzing the numerical data gathered through systematic observation and experimenta-
tion. Statistics allow researchers to do all of these things in a meaningful, logical fashion.Learning Objectives
A.1 Explain why statistics are important to psychologists and
psychology majors.
A.2 Describe the types of tables and graphs that represent patterns in
data.
A.3 Identify three measures of central tendency and explain how they
are impacted by the shape of the distribution.
A.4 Identify the types of statistics used to examine variations in data.
A.5 Describe how inferential statistics can be used to determine if
differences in sets of data are large enough to be due to something
other than chance variation.
A.6 Explain how statistics are used to predict one score from another.What Are Statistics?
A.1 Explain why statistics are important to psychologists and psychology majors.
Many students in psychology wonder why the field uses such seemingly complicated
mathematics. The answer is easy. Psychologists base their field on research findings. Data
are collected, and they have to be analyzed. Statistics is the field that gives us the tools to
do that.
Psychologists have to be able to do two things with the data they collect. The first is
to summarize the information from a study or experiment. The second is to make judg-
ments and decisions about the data. We are interested if groups differ from each other.
We are also interested in how one group of variables is related to another.
Statistics is the branch of mathematics that is concerned with the collection and
interpretation of data from samples (Agresti & Finlay, 1997; Aron et al., 2005). A sample
is a group of people selected, usually randomly, from a larger population of people. If
you asked what the average height of teenage males was, and you calculated the average
from just your high school, that average would be a statistic.
Statistical analysis is a way of trying to account for the error that exists in almost
any body of data. Psychology is only one of many fields that use the following types
of statistics.Appendix
A
statistics
branch of mathematics concerned
with the collection and interpretation
of numerical data.sample
group of subjects selected from a
larger population of subjects, usually
selected randomly.Z01_CICC7961_05_SE_APPA.indd 1 9/2/16 11:57 PM