Bisakah saya mendapatkan bantuan untuk menyelesaikan upaya sementara (sedang berlangsung) untuk mendapatkan posisi yang sesuai dengan ANOVA dan REGRESI? Saya telah berusaha mendamaikan konsep, nomenklatur dan sintaksis dari kedua metodologi ini. Ada banyak posting di situs ini tentang kesamaan mereka, misalnya ini atau ini , tetapi masih bagus untuk memiliki peta "Anda di sini" yang cepat ketika memulai.
Saya berencana memperbarui posting ini, dan berharap mendapatkan bantuan memperbaiki kesalahan.
ANOVA satu arah:
Structure: DV is continuous; IV is ONE FACTOR with different LEVELS.
Scenario: miles-per-gal. vs cylinders
Note that Income vs Gender (M, F) is a t-test.
Syntax: fit <- aov(mpg ~ as.factor(cyl), data = mtcars); summary(fit); TukeyHSD(fit)
Regression: fit <- lm(mpg ~ as.factor(cyl), mtcars)
# with F dummy coded;
summary(fit); anova(fit)
ANOVA dua arah:
Structure: DV is continuous; IV is > 1 FACTORS with different LEVELS.
Scenario: mpg ~ cylinders & carburators
Syntax: fit <- aov(mpg ~ as.factor(cyl) + as.factor(carb), mtcars);
summary(fit); TukeyHSD(fit)
Regression: fit <- lm(mpg ~ as.factor(cyl) + as.factor(carb), mtcars)
# with F dummy coded;
summary(fit); anova(fit)
ANOVA faktorial dua arah:
Structure: All possible COMBINATIONS of LEVELS are considered.
Scenario: mpg ~ cylinders + carburetors + (4cyl/1,...8cyl/4)
Syntax: fit <- aov(mpg ~ as.factor(cyl) * as.factor(carb), mtcars);
summary(fit); TukeyHSD(fit)
Regression: fit <- lm(mpg ~ as.factor(cyl) * as.factor(carb), mtcars)
# with F dummy coded;
summary(fit); anova(fit)
ANCOVA:
Structure: DV continuous ~ Factor and continuous COVARIATE.
Scenario: mpg ~ cylinders + weight
Syntax: fit <- aov(mpg ~ as.factor(cyl) + wt, mtcars); summary(fit)
Regression: fit <- lm(mpg ~ as.factor(cyl) + wt, mtcars)
# with F dummy coded;
summary(fit); anova(fit)
MANOVA:
Structure: > 1 DVs continuous ~ 1 FACTOR ("One-way") or 2 FACTORS ("Two-way MANOVA").
Scenario: mpg and wt ~ cylinders
Syntax: fit <- manova(cbind(mpg,wt) ~ as.factor(cyl), mtcars); summary(fit)
Regression: N/A
MANCOVA:
Structure: > 1 DVs continuous ~ 1 FACTOR + 1 continuous (covariate) DV.
Scenario: mpg and wt ~ cyl + displacement (cubic inches)
Syntax: fit <- manova(cbind(mpg,wt) ~ as.factor(cyl) + disp, mtcars); summary(fit)
Regression: N/A
DALAM FAKTOR DALAM (atau SUBYEK) ANOVA: ( kode di sini )
Structure: DV continuous ~ FACTOR with each level * with subject (repeated observations).
Extension paired t-test. Each subject measured at each level multiple times.
Scenario: Memory rate ~ Emotional value of words for Subjects @ Times
Syntax: fit <- aov(Recall_Rate ~ Emtl_Value * Time + Error(Subject/Time), data);
summary(fit); print(model.tables(fit, "means"), digits=3);
boxplot(Recall_Rate ~ Emtl_Value, data=data)
with(data, interaction.plot(Time, Emtl_Value, Recall_Rate))
with(data, interaction.plot(Subject, Emtl_Value, Recall_Rate))
NOTE: Data should be in the LONG FORMAT (same subject in multiple rows)
Regression: Mixed Effects
require(lme4); require(lmerTest)
fit <- lmer(Recall_Rate ~ Emtl_Value * Time + (1|Subject/Time), data);
anova(fit); summary(fit); coefficients(fit); confint(fit)
or
require(nlme)
fit <- lme(Recall_Rate ~ Emtl_Value * Time, random = ~1|Subject/Time, data)
summary(fit); anova(fit); coefficients(fit); confint(fit)
SPLIT-PLOT: ( kode di sini )
Structure: DV continuous ~ FACTOR/-S with RANDOM EFFECTS and pseudoreplication.
Scenario: Harvest yield ~ Factors = Irrigation / Density of seeds / Fertilizer
& RANDOM EFFECTS (Blocks and plots of land):
Syntax: fit <- aov(yield ~ irrigation * density * fertilizer +
Error(block/irrigation/density), data); summary(fit)
Regression: Mixed Effects
require(lme4); require(lmerTest);
fit <- lmer(yield ~ irrigation * fertilizer +
(1|block/irrigation/density), data = splityield);
anova(fit); summary(fit); coefficients(fit); confint(fit)
or
library(nlme)
fit <- lme(yield ~ irrigation * variety, random=~1|field, irrigation)
summary(fit); anova(fit)
DESAIN NESTED: ( kode di sini )
Structure: DV continuous ~ FACTOR/-S with pseudoreplication.
Scenario: [Glycogen] ~ Factors = Treatment & RANDOM EFFECTS with Russian-doll effect:
Six rats (6 Livers)-> 3 Microscopic Slides/Liver-> 2 Readings/Slide).
Syntax: fit <- aov(Glycogen ~ Treatment + Error(Rat/Liver), data); summary(fit)
Regression: Mixed Effects
require(lme4); require(lmerTest)
fit <- lmer(Glycogen ~ Treatment + (1|Rat/Liver), rats);
anova(fit); summary(fit); coefficients(fit); confint(fit)
or
require(nlme)
fit<-lme(Glycogen ~ Treatment, random=~1|Rat/Liver, rats)
summary(fit); anova(fit); VarCorr(fit)
SITUS BERMANFAAT:
cyl + hp
. Horespower kontinu, jadi tidak berfungsi di sini.carb
, jumlah karburator akan menjadi pilihan yang lebih baik.