PSYC 333 Lecture Notes - Lecture 5: Total Variation, Location Test, Factorial Experiment
7 May 2018
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PSYC 305 – STATISTICS FOR EXPER DESIGN, WINTER 2018
Lecture 5: Two-Way ANOVA I
Midterm Exam will be on MARCH 1ST, Thursday, from 11:40 am to 12:30 pm.
Comparing Means...
One mean
z-test
One-sample t-test
Two means, one factor
Independent samples t-testMore than two means, one
factor
One-way ANOVA
More than two means, TWO factors
Two-way ANOVA
Independent samples t-test
Only one independent variable
(factor), and it has only 2 levels
(i.e., men & women) so we’ll
compare 2 groups on some
dependent variable (e.g., exam
score), continuous data. and then
it can be normally distributed.
(in this class, always continuous
for ANOVA)
find more resources at oneclass.com
find more resources at oneclass.com
PSYC 305 – STATISTICS FOR EXPER DESIGN, WINTER 2018
e.g., the effect of nationality on
exam scores. compare mean
scores. if at least one of these
means is diff from other means,
then we can say that there is
some effect of nationality on
exam scores.
each factor has multiple levels
Two-Way Factorial Experiments
We focus on experiments with TWO independent variables or factors.
Factorial designs are those in which factors are completely crossed.
contains all possible combinations of the levels of factors.
When each factor has 3 levels, it is called a 3 x 3 factorial
design, resulting in a total of 9 treatment combinations.
W
e have two factors at the same time, our design will be crossed. crossed = all
possible conditions of 2 factors will be considered
find more resources at oneclass.com
find more resources at oneclass.com
PSYC 305 – STATISTICS FOR EXPER DESIGN, WINTER 2018
here, we look at 9 combinations at once.
We further assume that
subjects serve only in one of the treatment conditions
(independent-groups design)
sample sizes are equal in each condition (balanced
design).
We will refer to the two independent variables as Factor A (Row) and
Factor B (Column).
Example: 2 x 2 Factorial Design
Zentall, S. S., & Shaw, J. H. (1980). Effects of classroom noise on
performance and activity of second-grade hyperactive and control children.
Journal of Educational Psychology, 72, 830-840.
Two groups of 2nd grade children (hyperactive and non-
hyperactive) solved math problems under high-noise and low-noise
conditions.
W
e have two factors., which have two
levels each.
thus, called 2x2, in total we have 4
diferentf conditions
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Midterm exam will be on march 1st, thursday, from 11:40 am to 12:30 pm. Independent samples t-test more than two means, one factor. Two-way factorial experiments each factor has multiple levels. We focus on experiments with two independent variables or factors. Factorial designs are those in which factors are completely crossed. Contains all possible combinations of the levels of factors. When each factor has 3 levels, it is called a 3 x 3 factorial design, resulting in a total of 9 treatment combinations. We have two factors at the same time, our design will be crossed. crossed = all possible conditions of 2 factors will be considered. Psyc 305 statistics for exper design, winter 2018 here, we look at 9 combinations at once. Subjects serve only in one of the treatment conditions (independent-groups design) Sample sizes are equal in each condition (balanced design). We will refer to the two independent variables as factor a (row) and.
