ANOVA Flashcards
A Normal distribution is?
Symmetric
Bell shape curve
The most probable values on a normal distribution are around?
Around the average
(top of bell curve)
The increasingly less probable values on a normal distribution are?
Further away from that average (bottom of bell curve)
The parameters for the normal distribution are?
Constant values that determine the shape and position of the distribution
Mean, μ (Greek letter mu) – i.e., the average: determines where the peak of the distribution is located.
Standard deviation, σ (Greek letter sigma) – i.e., the variability: determines the spread of the distribution.
The H0 (Null) is true when the 2 population distributions on a graph are?
Mostly overlapping
In order to decide to accept or reject the hypothesis, what do we have to take into consideration?
The means μ1 and μ2
of the 2 populations
Is their difference due to chance?
Chance refers to all uncontrolled sources of variability in an experiment. Generally, this variability is called what?
Experimental error
EXPERIMENTAL ERROR?
Further divided into 2 main types of error:
Measurement error
Individual differences error
MEASUREMENT ERROR
Methods used to measure variable is wrong/ biased/ flawed
This creates a systematic error and you may find an effect that was not due to the DV
(Eg- using 2 different methods to measure control and IV groups cognitive ability)
When subjects have naturally occurring differences that are hard to control, these differences will lead to deviation of sample distributions from the target population
even under identical treatments and with Zero measurement error (ZME), what is this known as?
INDIVIDUAL DIFFERENCES ERROR
Which error is typically more extreme when small sample sizes (denoted N) are used?
Individual Differences Error
What is the equation for the Total Deviation?
Between groups
deviation
÷
Within groups
deviation
= Total deviation
If the between groups deviation is large what does that suggest about Exam results and Lecture teaching styles?
The exam scores are highly affected by the lecture teaching styles
Between groups variance helps us to explain?
Estimates the treatment effects
The experimental error
Within groups variance helps us to explain?
Estimates experimental error ONLY
Each individual has an exam score and that score is subtracted from the mean average across both of lecture teaching style conditions.
What is this statement referring to?
Total Deviation
What is the name of the ratio ANOVA uses?
F-ratio
Between and Within
both to test the H0
What is the equation for Variance?
Variance=
Sum of Squares
÷ Degrees of freedom
The Sum of Squares SS
(Within Groups)
Take the Within Groups deviation
square it
Then times that accross every subject in both groups
The Sum of Squares SS
(Between Groups)
Take the Between Groups deviation
square it
Then times that across every subject in both groups
What does SS Total stand for?
Sum of Squares Total
The Sum of Squares Total can be calculated by?
Take the Total deviation (Difference between every student exam score - grand mean of both groups)
square it
Then times that by every individual subject and the number of groups
What does this represent:
SS 𝑇= SS𝑅 + SS𝐴
Sum of Squares Total =
Sum of squares Withing Groups
+
Sum of Squares Between Groups
The normal distribution can be described by which 2 parameters?
mean μ
and standard deviation σ
Our goal in analysis of variance (ANOVA) is to determine…
whether an observed difference in sample means can be generalised to population means,
given our uncertainty about these
Why do smaller sample sizes result in more uncertainty?
Because parameters vary more across samples
