Unit 8
Nonparametric Tests: Chi-square and MannWhitney U
Introduction
To date, we have focused primarily on parametric hypothesis testing procedures. Parametric
statistical procedures are those, like t-test and ANOVA, that analyze data that is interval or
Unit 1
Self-test
The following will help you further consolidate the information in unit 1. These questions
do not need to be handed in for credit but will help prepare you for the final exam.
The answers to the multiple-choice questions are found in the
Sample Final Exam
Multiple choice questions
Read each question carefully, and on the bubble sheet provided code the best
answer. Each question is worth 1 mark.
Questions (80 questions, 1 point each)
1. An Education researcher collects data on how many stu
Statistics for Psychology, 6e (Aron/Coups/Aron)
Chapter 1 Displaying the Order in a Group of Numbers
Using Tables and Graphs
1) A psychologist who constructs a frequency table to summarize data collected on the
amount of stress people have experienced in
Psych 2260
Research Methods
Jan. 17, 2014
Lecture 5
Alertness scores for those who get 6 hours of sleep (the null distribution)
we expect that only 2% would have an alertness score of z = >2
Q: if only 2% of those who sleep 8 hours have alertness scores o
Psych 2260
Research Methods
Jan. 10, 2014
Lecture 2
Symmetry and Skew
Symmetrical Distribution
values are more or less balanced on either side of the midpoint of the distribution
Normality and Kurtosis
the normal curve (bell shaped) is the standard of com
Psych 2260
Research Methods
Jan. 15, 2014
Lecture 4
ex. the probability of a Z-score between 0 and +1 is 34%
34% p=.34
What do we mean when we say p < 0.05?
Consider a simple example
male height in population:
Mean = 5 9
SD = 3
68% of males would be betwe
PSYC 2260
Research Methods
Mar. 5 2014
Lecture 17
Further effects of Dichotomizing
Loss of Power:
could lead to Type II error (missing important effects if they exist)
could also lead to Type I error (saying an effect exists when in reality it doesnt)
Bot
Psych 2260
Research Methods
Jan. 27, 2014
Lecture 8
Chapter 6: Making Sense of Statistical Significance
Decision Errors
recall: stats is about probability - not certainty
thus: always a chance that conclusion is wrong
Two kinds of decision errors:
1. Type
Psych 2260
Research Methods
Jan. 22, 2014
Lecture 7
as n gets larger, standard error gets smaller:
= 2/4 = 0.50
/ n
= 2/10 = 0.20
/ n
3. the shape of the distribution of means is normal
with repeated samples, extremes cancel out: the mean is pulled to t
Psych 2260
Research Methods
Jan. 29, 2014
Lecture 9
Effect size sample:
IQ has: 100 15
=
=
test group has: M = 110
d = 110-100 / 15 10/15 d=0.666
.67 = medium effect size
Effect Size and Meta-Analysis:
recall form chapter 3:
one use of Z-scores is to stan
Psych 2260
Research Methods
Jan. 20, 2014
Lecture 6
Chapter 5: Hypothesis tests with means of samples
"The Distribution of Means"
A distribution of means (rather than raw scores)
Used for testing hypotheses about samples (rather than individuals)
Recall f
Psych 2260
Research Methods
Jan. 13, 2014
Lecture 3
*Look Ahead Note
Definitional Formulas will be used for lab assignments because it facilitates understanding and
is the common layout for these types of calculations
Common Layout:
X
X-M (X-M)2
X
X-M)2
Psych 2260
Research Methods
Jan. 8, 2014
Lecture 1
Chapter 1: Displaying Order
Two branches of statistics:
1. Descriptive: to summarize and describe order, pattern or structure in a group
of numbers
2. Inferential: based on the numbers, but used to infer
PSYC 2260
Chapter 14
Strategies when Population Distributions
are not normal
- This chapter examines some strategies researchers use for hypothesis testing when the assumptions of normal
population distributions and equal variances are clearly violated.
A
Psyc 2260
Chapter 5
Hypothesis tests with Means of Sample
The distribution of means :
- distribution of means distribution of means of samples of a given size from a population (also called a sampling
distribution of the mean); comparison distribution whe
Psyc 2260
Chapter 1
Displaying the Order in a Group of Numbers Using Tables and Graphs
- statistics is a branch of mathematics that focuses on the organization, analysis, and interpretation of a group
of numbers
- In other words, statistics is a method of
Psyc 2260
Chapter 9
Introduction to the Analysis of Variance
(ANOVA)
- The statistical procedure for testing variation among the means of more than two groups is called the analysis of
variance, abbreviated as ANOVA.
- To emphasize the difference from fac
Chapter 8 : The t test for Independent Means
- me men measured on communication quality before and after premarital counseling). In this chapter, you learn how to
compare two sets of scores, one from each of two entirely separate groups of people.
- t tes
PSYC 2260
Research Methods
Mar. 3 2014
Lecture 16
interaction is indicated by nonparallel lines
3 Hypotheses in a 2X2 Design:
2 Main Effects hypotheses:
1. For factor A - sleep vs. no sleep
(null: sleep makes no difference)
2. For factor B - coffee vs. no
Answers to Self-Test Questions
Unit 1
Consolidate 1.1
1.
2.
3.
4.
5.
b
a
b
a
d
Consolidate 1.2
1.
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4.
e
b
b
b
Self-test
Multiple-choice questions
1.
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3.
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5.
6.
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8.
9.
10.
d
b
b
c
b
e
d
d
a
c
Introduction to Research Methods in Psychology
PSYC 2
Sample Final Exam Answers
Multiple choice answers
1.
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5.
6.
7.
8.
9.
10.
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b
a
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d
c
c
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d
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a
c
d
a
b
b
c
b
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d
Unit 7
ANOVA (Analysis of Variance)
Introduction
Researchers often have more than two groups, levels, or treatments in their research designs (e.g.,
placebo, low, medium, and high drug dose groups), and they want to know if any one mean in the
group is di
Unit 6
The T-Tests
Introduction
The t-test is one of simplest, yet most telling, statistics that researchers use when they are
assessing whether or not their manipulation of the independent variable produced significant
changes in the dependent variable.
Unit 7
Self-test
The following will help you further consolidate the information in unit 7. These questions
do not need to be handed in for credit but will help prepare you for the final exam.
The answers to the multiple-choice questions are found in the
Unit 8
Self-test
The following will help you further consolidate the information in unit 8. These questions
do not need to be handed in for credit but will help prepare you for the final exam.
The answers to the multiple-choice questions are found in the
Unit 6
Self-test
The following will help you further consolidate the information in unit 6. These questions
do not need to be handed in for credit but will help prepare you for the final exam.
The answers to the multiple-choice questions are found in the
Unit 5
Self-test
The following will help you further consolidate the information in unit 5. These questions
do not need to be handed in for credit but will help prepare you for the final exam.
The answers to the multiple-choice questions are found in the
Unit 5
Statistical Significance, Power, and Effect Size
Introduction
The goal of this unit is to make you a better consumer of statistical results. Although the significance
(p < 0.05) level of any research result is undoubtedly the most important single
Unit 3
Inferential Statistics: The Basics
Introduction
When psychologists make conclusions that go beyond their particular sample, they base these
conclusions on inferential statistics. Inferential statistics are fairly complex mathematical procedures
bas
PSYC 2260
Chapter 13
Chi-Square Tests
chi-square tests : hypothesis-testing procedures used when the variables of interest are nominal variables.
- the scores that you will encounter in this chapter represent frequencies: that is, how many people or obse
PSYC 2260
chapter 7
Introduction to "t tests" : Single Sample and
Dependent Means
- the procedures of hypotheses whatever you learned before will not help you as a researcher but will help u to
understand the next procedures
- these procedures involve a c
PSYC 2260
Chapter 11
Correlations
- this chap : to look at the relationship between two groups of scores.
- Ex : the group of scores for doing exciting things and the group of scores for marital satisfaction
- in general, this graph shows that the less pe
Psyc 2260
Chapter 6
Making sense of Statistical Significance
- decision errors incorrect conclusions in hypothesis testing in relation to the real (but unknown) situation, such as
deciding the null hypothesis is false when it is really true.
- There are t
PSYC 2260
chapter 2
Central Tendency and Variability
- a representative value gives us a central tendency for a grp of scores
- the main representative value we consider is Mean
- variability : how the numbers are spread out in the number of scores
- Cent