Distributions
Normal Distribution
what are normal population parameters and equal central tendency (mean, median, mode)
Experimental Design
What is manipulation
Has control and Random Assignment
Correlation
A relationship between two or more variables
Sample
A subset of data (comes from the population)
Pearson R Correlation
Looks at the relationship between two or more variables
Determines the Strength and Direction
Skewed Distribution
What is a violation of population parameters
This leads to underestimated correlations
Leads to Type II Errors
Non- Experimental Design
- no control or random assignment
Population
The entire population which you are studying
Control
All variables are under the same influence
Positively Skewed Distributions
Correlation
.43 is a moderate and positive relationship
-.43 is a negative/moderate relationship
Are more precise because it looks at the influence of other variables
Regressions
Are a predictor between 1x and 1y
r2 change
Negatively Skewed Distribution
Tail is headed in the negative direction
a difference between two groups
You reject the null when you shouldnt have (the null is true)
Multiple Regressions
p < .05
95% confident
5% doubt
"I am 95 confident that this is not due to chance."
What are the characteristics of a normal distribution
1 SD -- 68%
2 SD -- 95%
3 SD-- 99%
Random Selection
Ensures Representativeness; everyone has an equal opportunity to be selected
Type 2 Error
You fail to reject the null -- you say there is no difference when there actually is
Benefits of a Factorial ANOVA
Reduce Type I error
Look at the interactions
Ceiling and Floor Effect
Ceiling -- when the mode is the highest possible value
Floor - when the mode is the lowest possible value