Chapter 11 Flashcards
Group condition means
average score on the DV for each grop
SV
difference between groups
EV
can also be the cause for the difference in group means, variability caused by variables other than IV
inferential statistics
used to test whether a difference between group means is larger than what would be expected on the basis of error variance alone
p-value
probability we would get the observed difference between group means even if the IV had no effect
if p value is small
we conclude that the IV likely caused the difference between group means
a difference between means that is statistically significant is
unlikley due to error variance
null hypothesis
group means are equal, IV had no effecte
experimental hypothesis
group means are not equal; IV had an effect
type 1 error
reject the null when it is true
probability of type 1 error
alpha level
type 2 error
fail to reject the null when it is false
effect size
strength of the relationship between variables
variance accointed for
proportion of variance in one variable that is accounted for by another variable
Cohens d
standardized difference, difference between group means divided by error varaince
criticism of null hypothesis
a p-value does not tell you how large an effect us
confidence interval
the range of likey values for the population mean
