Practice Problems/Analyses: ANSWERS IN RED
1. Recode the Treatment Satisfaction variable into the following levels and name
your new variable KH_TreatSat_Groups (using your initials).
a. 1 = Low Satisfaction (0 - 33)
b. 2 = Moderate Satisfaction (34 - 65)
PSY 2301 Lecture 10
Independent t Test
Yueqin Jean Hu
Teaching Goal
To introduce the basic characteristics of an
independent-measures (or between-subjects)
research design.
To demonstrate the process of hypothesis testing
with the independent-measures t
PSY 2301: Final Exam
The final exam will consist of approximately 75 multiple-choice questions (approximately 50
questions related to the last portion of the course material: Correlation & regression and Chi 2
tests, and 25 review questions).
The question
HOW TO MATCH RESEARCH QUESTIONS WITH CORECT
STATISTICAL TESTS
Follow the Steps:
1. Is variable that was measured/reported a nominal measurement (i.e., a frequency count such
as how many women versus man had a car accident during the last month)?
If the an
Organizing data: Frequency distribution of scores
Tables
Graphs
Ungrouped Frequency Distribution
Data Set:
2, 7, 10, 5, 5, 3, 9, 12, 5, 8, 2, 4, 7, 6, 10, 7,
3, 9, 7, 12, 4, 6, 3, 2, 8.
X = a single score
f = frequency associated with each score
n = 25
Empirical Research & Statistics
Statistics = mathematical procedures to organize,
summarize & derive conclusions from systematic measurements
(i.e., empirical research)
Empirical Research & Statistics
Steps in a typical research project
Formulate research
MEASURES OF CENTRAL TENDENCY
(a single score that defines the center of a distribution)
Mean (i.e., arithmetical average)
Median
Mode
MEAN
The sum of all the scores divided by the number of scores in the data.
The amount each individual receives when t
Z-scores
Standardized distributions
Two distributions of exam scores
Z-score
identifies location of a score (X) within the distribution of all scores
Population:
X
z
Sample:
X M
z
s
Interpretation of a z-score
The sign of z-score tells whether the score
Two Independent Samples
Two Independent Samples
Two basic types of experimental designs
Between-groups/subjects or independent-measures
or independent-groups design:
datasets from two completely separate groups/samples
Repeated-measures or dependent- o
Repeated-Measures Designs
Repeated-Measures Designs
Repeated measures design:
also known as within-subjects, dependent- or
related-samples, repeated-measures design
two measures (i.e., 2 scores are obtained for each
individual in the sample; the same s
The Distribution of Sample Means
The Distribution of Sample Means
http:/www.nytimes.com/video/science/100000002452709/bunnies-dragons-a
nd-the-normal-world.html?smid=pl-share
Distribution of Sample Means
Distribution of Sample Means
The distribution of s
2101 Introduction to Statistics Lab 2
Frequency Distributions
Bar Graphs and Histograms
Open the Lab 2 SPSS dataset.
Frequency Tables
1. To create a Frequency Table, you will click on the following sequence:
Analyze-> Descriptive Statistics-> Frequencies.
Choosing Statistical Tests
Univariate Tests
Correlation Both the IV and DV are Continuous
One-Sample t-Test IV = Sample/General Population; DV = Continuous
Paired t-Test IV = Same Sample at 2 Time Points; DV = Continuous
Independent t Test IV = Nominal 2
PSY 2301 Lecture 11
Paired Sample t Test
Yueqin Jean Hu
Teaching Goal
To introduce the basic characteristics of a
repeated-measures (or within-subjects)
research design
To demonstrate the process of hypothesis
testing with the repeated-measures t
To intro
PSY 2301 Lecture 13
Repeated-Measures Analysis of Variance
Yueqin Jean Hu
Teaching Goal
To introduce the logic underlying the
repeated-measures analysis of variance.
To demonstrate the similarities and
differences between a repeated-measures
ANOVA and a
PSY 2301 Lecture 14
Two-Factor Analysis of Variance
Yueqin Jean Hu
Teaching Goal
To introduce the concept of a two-factor
research design.
To introduce the concepts of main effects
and interactions
To demonstrate the process of hypothesis
testing with the
PSY 2301 Lecture 12
Analysis of Variance
Yueqin Jean Hu
Teaching Goal
To introduce the logical foundation for analysis of variance
(ANOVA)
To demonstrate the process of hypothesis testing with ANOVA
To demonstrate the use of post tests to help interpre
2101 Introduction to Statistics Lab 10
Correlations
A Correlation is used when evaluating the strength of the relationship between two variables.
These variables are measured on ordinal or interval/ratio scales (not nominal).
A Pearson Correlation is used
2101 Introduction to Statistics Lab 9
Factorial ANOVA
Like the One-Way ANOVA, Factorial ANOVA tests mean differences between groups and the
Dependent Variable is measured on an Interval/Ratio scale. However, instead of a single
Independent Variable, Facto
2101 Introduction to Statistics Lab 6
One-Sample and Independent t-tests
Overview of t-tests: The t-tests are used when comparing the means of two groups. There are
three different types of t-tests: one-sample, independent and paired. Lab 6 covers one-sam
2101 Introduction to Statistics Lab 7
New: Paired t-Tests
Practice: One-Sample, Independent and Paired t-Tests
Paired t-tests (AKA: Dependent t-tests, Repeated-Sample t-tests, and Matched t-tests)
Paired t-tests are typically used when comparing the same
2101 Introduction to Statistics Lab 5
Compute Function and Recode Function
Transformations: Creating new variables based on other variables
Compute Variable (Transform -> Compute Variable)
In Survey Research, we will ask participants a series of questions
2101 Introduction to Statistics Lab 3
Measures of Central Tendency
Measures of Variation
Open the SPSS Lab 3 data set.
Part I: Central Tendency
Review: Central Tendency is a single value that best describes the center of the data set. There
are 3 Measures
Chi2 tests
It is used to analyze data recorded on a nominal scale
(i.e., frequency counts inside separate nominal
categories)
E.g., Frequency count of male and female
students who buy Pepsi, Coke, Sprite etc., in
a school cafeteria to test if there is a g
Two-Factor ANOVA for independent groups
In one-factor ANOVA groups correspond to different levels of one
independent variable
In two-factor ANOVA effects of two independent variables are tested
In the simplest version 2 independent variables, each with
One Factor ANOVA Worksheet
1. Researchers studied factors affecting the presence of harmful insects in farm fields. They set out
boards covered with a sticky material and then examined the insects trapped on the boards. To
investigate which colors are mos
The t Test for Independent Samples
1. In a study of jury behavior, two samples of participants were provided details about a trial in which the
Page | 1 was obviously guilty. Although group B received the same details as group A, the second
defendant
grou
One Factor ANOVA Worksheet ANSWERS
1. Researchers studied factors affecting the presence of harmful insects in farm fields. They set out
boards covered with a sticky material and then examined the insects trapped on the boards. To
investigate which colors
Hypothesis Testing Practice ANSWERS
1. National health statistics show that the mean weight for 2-year-old children is = 26 pounds.
The distribution of weight is normal with = 4 pounds. The researchers plan is to obtain a
sample of n = 16 newborn infants
Repeated Measures ANOVA Practice
Problems
1. This is data from an experimental study evaluating the effects of different types of distraction on
the performance of a visual detection task. The participants task is to detect a very faint visual
stimulus un
Repeated Measures ANOVA Practice
Problems
1. This is data from an experimental study evaluating the effects of different types of distraction on the
performance of a visual detection task. The participants task is to detect a very faint visual stimulus un
Two Way ANOVA Practice Problems
1.
The table below gives the number of pounds lost over six months in a study in which the effect of behavior modification and
group therapy was compared for clients who paid $10, $20 or $30 per session. 30 people were rand
The t Test for Repeated-Measures
1. A psychiatrist wishes to determine whether a new medication controls seizures better
than the patients previous medications. The number of seizures is recorded on previous
and new medications for a period of 1 year for
Hypothesis Testing Practice ANSWERS
1. National health statistics show that the mean weight for 2-year-old children is = 26
pounds. The distribution of weight is normal with = 4 pounds. The researchers plan is
to obtain a sample of n = 16 newborn infants
Probability and Sampling Distribution Practice
1.Why are z-scores referred to as "standard scores?"
2. Dr. Jones has administered a test to her students. She calculated a mean of 86 and a standard deviation of 12.
a. What is the z-score of a student with