Week 4 Flashcards
Outlier
Score very different to the rest. Can influence mean and the error.
3 contexts of bias
- Things that bias parameter estimates (inc effect sizes)
- Things that bias SE & CI
- Things that bias test statistics and p-values
What can bias estimates of parameters and drastically affect sum of errors?
Outliers
Assumption of normality
Look at central limit theorem
T-test limitations
- Can only be applied to populations similar to rest sample
- Sample and pop should be normal I.e. Bell curve
- Same no of scores
How big should sample be to kick in central limit theorem?
At least 30
Homogeneity of variance
Audiologist. Spread of scores around mean is roughly the same
Heterogeneity of variance
Scores are spread out around the mean. Scores different each occurance.
Unbiased heterogeneity and homogeneity of variance
Least method of squares. Or weighted least squares
Homogeneity of variance matters when…
U want to look at confidence intervals around model parameter estimates or test model significance
P-p plot (probability-probability plot)
Graph to check normality. Plots cumulative probability of a variable against cumulative prob of particular distribution
Homogeneity
The same
Heterogeneity
Different
Variance
Represents the spread of data
Tests of normality
S-W test
K-S test