Class Notes (1,100,000)

CA (620,000)

McGill (30,000)

PSYC (4,000)

PSYC 305 (50)

Heungsun Hwang (50)

Lecture 8

# PSYC 305 Lecture Notes - Lecture 8: Null Hypothesis, Random Assignment, Type I And Type Ii Errors

by OC13018

This

**preview**shows page 1. to view the full**4 pages of the document.**PSYC305 Lecture 8 - Feb. 1

One-Way ANOVA:

•Assume all three populations all have the same variances

Assessing Normality:

•Look at descriptive statistics

•Skewness 0≃

•> 0 - positively/right skew

•< 0 - negative/left skew

•Look at their standard errors

•If it is normally distribution, there is no skewness

•If it is skewed, technically you can’t apply the one-way ANOVA

•Construct charts

•Separate histograms for each group to assess normality

•It doesn’t have to be perfect, just roughly symmetric

•Evaluate a normal quantile plot (or normal probability plot)

•Sort observations from smallest to largest

•Calculate the z-scores of the sorted observations

•Plot the observations against the corresponding z-scores

•If the data are closed to normal, then the points will lie close to some straight

line

•Statistical tests of normality:

•The Kolmogorov-Smirnov (K-S) test

•The Shapiro-Wilk test

•Compares sample scores to a set of scores generated from a normal distri-

bution with the sample means and standard deviation

###### You're Reading a Preview

Unlock to view full version