Lecture 1 Flashcards
Why are these techniques important?
One-Way Between-Subjects Analysis of Variance Intro
Bivariate regression analysis intro
Multiple regression analysis intro
Bivariate binary logistic regression analysis intro
Multiple binary logistic regression analysis intro
Summary table
One-Way Between-Subjects
Analysis of Variance: Substantive hypothesis:
A person’s degree of organizational commitment (Y) depends on the team in
which the person works (X)
Question for One-Way Between-Subjects
Analysis of Variance hypothesis
if the hypothesis is correct, what would you expect to find with
regard todifferences in average commitment between the teams?
Key idea of ANOVA is:
When there are 2 or more groups, can we make a statement about possible
-significant- differences between the mean scores of the groups?
Fundamental principle of ANOVA:
ANOVA analyses the ratioof the two components of total variance in data:
between-group variance and within-group variance
information on variance of average scores between groups
/
information on variance of scores within groups
ANOVA analyses ratio in which between-group variancemeasures
systematic differences between groups and all other variables that influence
Y, either systematically or randomly (‘residual variance’or ‘error’)
and
within-group variancemeasures influence of all other variables that influence
Y either systematically or randomly (‘residual variance’or ‘error’)
Differences withina group
Any differences withina group cannotbe due to differences between
the groups because everyone in a particular group has the same group
score; so, within-group differences must be due to systematic
unmeasured factors (e.g., individual differences) or random
measurement error
Differences between groups
Any observed differences between groupsare probably not only pure
between-group differences, but also differences due to systematic
unmeasured factors or random measurement error
Null hypothesis
Mean scores of k populations corresponding to the groups in het study are
all equal to each other:
H : μ1= μ2=…= μk
Why prefer One-Way Between-S ANOVA instead of seperate t-tests for
means(Warner, p. 220)?
Why prefer One-Way Between-S ANOVA instead of seperate t-tests for
means(Warner, p. 220)?
Formula for calculation of chance of 1 or more Type I errors in a series of
C tests with significance level α:
F-distribution
In order to determine if a specific sample result is expectional (‘significant’)
under the assumption that the statistical null hypothesis is correct, the
test-statistic F has to be calculated
=testing hypothesis of variances.
Deviation of individual score from grand mean:
Yij - My
Deviation of individual score from group mean:
(Yij - Mi ) = εij
Deviation of group mean from grand mean:
(Mi - My) = αiù
αi denotes the ‘effect of group i’(do not confuse with significance level!)
(Yij - My) = (Yij - Mi) + (Mi - My)
Sums of Squares
Mean Squares
Sum of Squares/df:
(more on slides)
F Ratio test statistic
MSbetween / MSwithin
MSbetween formula
MSwithin