SPSS video lectures Flashcards
What is skewness?
tail leans to left or right
How can you get an indication of the normality (normal distribution) on the data depending on what?
By looking at the mean and the median. The closer they are, the more likely it is that its normally distributed. its just a relative question.
What is the rule of thumb for skewness and kurtosis?
an absolute value of one
When having a test of normality, what is the rule of thumb for the significance?
It needs to be above 0.05. Because a value under 0.05 indicates non-normality. (abnormal distribution).
How can you interpret a box plot?
The more symmetric the boxplot, the more normally distributed the data is.
What does it mean when we say that the correlation coefficient is significantly different from zero?
the correlation coefficient is significant
What is independent samples t-test? Give an example
Independent samples t-test is when we have to group means (like men vs women average income) that we want to compare to see if the means are significantly different from each other, the same or just random chance. in this case the two groups are not related to each other.
not to be compared wit repeated measure t-test: womens income at time 1 and then time 2. two dependent group (same group at different times)
What is Levenes test for equality of variances?
this is one of the assumptions of the independent samples t-test. the two groups should have equal variances. if we have quite different group sizes, there is a chance the variance will not be equal.
What is the standard cutoff for significance?
0.05
> 0.05 = equal variances
< 0.05 = would be significant difference
What is the rule of thumb for t-tests?
if the t value < 2, then its prob not significant
What are the rule of thumbs for Cohens D point estimate?
anything around 0.2 would be a small effect
< 0.2, dont interpret it
0.5 medium effect
0.8 large effect
What is paired samples/repeated measures t-tests?
you look at the same period but for different time periods. they are dependent on each other.
What does the significance level in a paired sampled t-test tell us?
if its < 0.05 we can say that there is a significant difference between the means
if its larger than > 0.05 the difference are by chance, there is no significant difference
What is Exploratory factor analysis?
It is a way of establishing construct validity which is made up of two parts: convergent validity and discriminant validity.
What is a latent construct? (EFA)
Something that is not directly observable, like collaboration or trust so we observe through ex a questionnaire. Everything in like colllaboration should converge. But other factors like trust should diverge from each other. (discriminant). because otherwise trust and collaboration is overlapping.