PSYC 2002 Introduction to Statistics in
Psychology
Week 1a: Course Introduction
John Logan
(updated: 2023-01-07)
Course Overview
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Course blurb for PSYC 2002 B
PSYC 2002 covers the basics of data analysis. It will build on
the descriptive statistics covered in PSYC 2001 but the major
focus is on inferential statistics. Inferential statistics
encompass a variety of procedures for deciding if results
obtained in a study are due to chance or not. You will learn
how to use these statistics as well as learn their underlying
conceptual basis. You also will learn how to use Excel and a
dedicated statistical package called Jamovi to do statistical
calculations and visually present data.
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Why is statistics a required course?
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Psychological Facts & Theories
psychological science produces facts and theories
1. facts are produced by collecting measurements about psychological
phenomena, and by running experiments to establish the root
causes of the phenomena
2. theories are working explanations of a set of facts; they describe
how causal forces work to produce the psychological phenomena
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Facts depend on Evidence
"facts" about psychology are only as good as the evidence for them
facts can be relied upon when the evidence for their existence is
indispustable (clear-cut); there are many reliable findings in
psychology
but, you should not believe every 'fact' you hear!
some findings in psychology are unreliable (other researchers
can't reproduce them), some are faked(!) and, others are
downright silly
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Theories must explain evidence
the whole point of theories is to explain evidence, or the credible facts
about a psychological phenomena of interest
many good, strong, theories in psychology exist and are capable of
explaining many aspects of psychological phenomena
BUT
you should not believe every theory you hear about in psychology!
Some "theories" do not explain the facts; some "theories" aren't
theories at all, they are just someone's opinion
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So...how can we trust the facts and theories in
Psychology?
You need to learn how to evaluate the evidence
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All psychology needs statistics
1. psychologists run experiments to test research questions and
claims
2. the experiments produce measurements, or evidence
3. statistics are used to evaluate the evidence
does the evidence support the claim?
does the evidence not support the claim?
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When you hear a scientific claim...
1. you could accept the claim because "a Scientist said it was true"
2. you could evaluate the evidence for claim and decide for yourself if
the evidence warrants the claim
Just because a scientist makes a claim, doesn't make it true
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The case of power-posing
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Can a powerful pose change your life?
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High vs. low power poses
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The evidence for power posing
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Power posing embraced by media
Amy Cuddy gave a TED Talk (viewed by 48 million people) arguing that
power posing can change your life
link to TED talk
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The problem
only a single study, with inconsistent evidence
many other labs tried to reproduce the findings, but they failed to
replicate the hormone change component of the study and found
inconsistent results for the behavioural component of the study
http://faculty.haas.berkeley.edu/dana_carney/ranehill.pdf
https://www.nytimes.com/2017/10/18/magazine/when-the-revolutioncame-for-amy-cuddy.html
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Current state of power posing
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Lessons learned
Lesson 1: don't believe everything you hear, even if it's published in a
scientific journal
Lesson 2: to understand psychological science, you must understand
how to evaluate evidence produced by psychological science
Lesson 3: statistical analysis cannot rescue a not-so-good experimental
design
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Next...
W1b: Statistics as a tool
Crump: Chapter 1
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