500 likes | 628 Vues
Quantitative Methods. Random Effects. Random Effects. What are random effects?. Random Effects. What are random effects?. Criterion: Fixed effects Random effects. Random Effects. What are random effects?. Repetition: If the experiment were repeated:. Criterion: Fixed effects
E N D
Quantitative Methods Random Effects
Random Effects What are random effects?
Random Effects What are random effects? Criterion: Fixed effects Random effects
Random Effects What are random effects? Repetition:If the experiment were repeated: Criterion: Fixed effects Random effects
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Criterion: Fixed effects Random effects
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to:
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random?
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another?
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant Do guppies swim faster at higher temperatures?
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant Do guppies swim faster at higher temperatures? Temperature Guppy
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant Do guppies swim faster at higher temperatures? Temperature Guppy
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant Do guppies swim faster at higher temperatures? Temperature Guppy Do starlings learn faster with higher rewards?
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant Do guppies swim faster at higher temperatures? Temperature Guppy Do starlings learn faster with higher rewards? Starling Reward
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant Do guppies swim faster at higher temperatures? Temperature Guppy Do starlings learn faster with higher rewards? Starling Reward
Random Effects What are random effects? Repetition:If the experiment were repeated: Same levels would be used Different levels would be used Criterion: Fixed effects Random effects Desired inference:The conclusions refer to: The levels used A population from which the levels used are just a (random) sample Applying the criteria: Fixed or random? Does one strain of barley grow faster than another? The strain The barley plant Do guppies swim faster at higher temperatures? Temperature Guppy Do starlings learn faster with higher rewards? Starling Reward The problem is a random effect produces an extra random term
Random Effects What are random effects?
Random Effects Why do random effects matter? 1. More than one random term 2. While the error is different for each datapoint, a random effect is not
Random Effects New concepts: components of variance Example: 10 starlings, each set 5 different foraging tasks and the time to learn was measured. Model formula is LEARNTIME = STARLINGS There are 50 random error terms, but 10 random starling terms. The EMS measures the size of the error variation. We also want to measure the size of the starling variation
Random Effects New concepts: expected mean square
Random Effects New concepts: expected mean square
Random Effects New concepts: nesting
Random Effects New concepts: appropriate denominators
Random Effects New concepts: appropriate denominators
Random Effects A one-way ANOVA with a random factor
Random Effects A one-way ANOVA with a random factor
Random Effects A one-way ANOVA with a random factor
Random Effects A one-way ANOVA with a random factor
Random Effects A one-way ANOVA with a random factor
Random Effects A one-way ANOVA with a random factor
Random Effects A one-way ANOVA with a random factor
Random Effects A one-way ANOVA with a random factor (2) + 4(1) = 0.01076+4*0.02072 = 0.09362
Random Effects A one-way ANOVA with a random factor (2) + 4(1) = 0.01076+4*0.02072 = 0.09362
Random Effects A one-way ANOVA with a random factor (2) + 4(1) = 0.01076+4*0.02072 = 0.09362 LEAF MS = 0.09362
Random Effects A two-level nested ANOVA
Random Effects A two-level nested ANOVA
Random Effects A two-level nested ANOVA
Random Effects A two-level nested ANOVA
Random Effects A two-level nested ANOVA
Random Effects A two-level nested ANOVA
Random Effects A two-level nested ANOVA
Random Effects Mixing random and fixed effects
Random Effects Mixing random and fixed effects
Random Effects Mixing random and fixed effects
Random Effects Mixing random and fixed effects
Random Effects Last words… • Nested and crossed. • Fixed or random? is a vital question. Tell by desired inference and repetition. • Be prepared for the complications... Categorical Data Read Chapter 13