dat <- read.csv("Assignment04", header = TRUE, sep = ",", stringsAsFactors = TRUE)

library(psych)
describeBy(value ~ condition, data = dat)

## 
##  Descriptive statistics by group 
## condition: Adjective
##       vars  n mean   sd median trimmed  mad min max range  skew kurtosis   se
## value    1 10   11 2.49     11   11.25 2.97   6  14     8 -0.66    -0.84 0.79
## ------------------------------------------------------------ 
## condition: Counting
##       vars  n mean   sd median trimmed  mad min max range skew kurtosis   se
## value    1 10    7 1.83      7       7 1.48   4  10     6    0    -1.22 0.58
## ------------------------------------------------------------ 
## condition: Imagery
##       vars  n mean  sd median trimmed  mad min max range skew kurtosis   se
## value    1 10 13.4 4.5   11.5   12.75 1.48   9  23    14 0.99    -0.53 1.42
## ------------------------------------------------------------ 
## condition: Intention
##       vars  n mean   sd median trimmed  mad min max range skew kurtosis   se
## value    1 10   12 3.74     11      12 2.97   5  19    14 0.05    -0.47 1.18
## ------------------------------------------------------------ 
## condition: Rhyming
##       vars  n mean   sd median trimmed  mad min max range skew kurtosis   se
## value    1 10  6.9 2.13    6.5    6.88 0.74   3  11     8 0.18     -0.4 0.67

level.aov <- aov(value ~ condition, data = dat)
summary(level.aov)

##             Df Sum Sq Mean Sq F value   Pr(>F)    
## condition    4  351.5   87.88   9.085 1.82e-05 ***
## Residuals   45  435.3    9.67                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

library(emmeans)

levels(dat$condition) #จาก package psych

## [1] "Adjective" "Counting"  "Imagery"   "Intention" "Rhyming"

contrast_m <- data.frame("Rhym.vs.Adj"                   = c(-1,    0,   0, 0,  1), 
                         "Adj.Coun.Imag.vs.Rhyming"      = c(1/3, 1/3, 1/3, 0, -1), 
                         row.names = levels(dat$condition))  
contrast_m

##           Rhym.vs.Adj Adj.Coun.Imag.vs.Rhyming
## Adjective          -1                0.3333333
## Counting            0                0.3333333
## Imagery             0                0.3333333
## Intention           0                0.0000000
## Rhyming             1               -1.0000000

level.emm <- emmeans(level.aov, ~ condition) #(aov object ที่เราสร้างไว้, ~ เงื่อนไข)
summary(level.emm)

##  condition emmean    SE df lower.CL upper.CL
##  Adjective   11.0 0.984 45     9.02    12.98
##  Counting     7.0 0.984 45     5.02     8.98
##  Imagery     13.4 0.984 45    11.42    15.38
##  Intention   12.0 0.984 45    10.02    13.98
##  Rhyming      6.9 0.984 45     4.92     8.88
## 
## Confidence level used: 0.95

contrast_results <- contrast(level.emm, method = contrast_m, adjust = "bonferroni", infer = TRUE)

contrast_results

##  contrast                 estimate   SE df lower.CL upper.CL t.ratio p.value
##  Rhym.vs.Adj                 -4.10 1.39 45   -7.325   -0.875  -2.948  0.0101
##  Adj.Coun.Imag.vs.Rhyming     3.57 1.14 45    0.933    6.200   3.141  0.0060
## 
## Confidence level used: 0.95 
## Conf-level adjustment: bonferroni method for 2 estimates 
## P value adjustment: bonferroni method for 2 tests