Step 2: Open the Installed Packages
library(readxl)
library(ggpubr)
## Loading required package: ggplot2
library(dplyr)
##
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
##
## filter, lag
## The following objects are masked from 'package:base':
##
## intersect, setdiff, setequal, union
library(effectsize)
library(effsize)
Loading the libraries
Step 3: Import and Name Dataset
Dataset6.1 <- read_excel("C:/Users/Navya/Downloads/Dataset6.1.xlsx")
Dataset is imported
Step 4: Calculate Descriptive Statistics for Each Group
Dataset6.1 %>%
group_by(Group) %>%
summarise(
Mean = mean(Exam_Score, na.rm = TRUE),
Median = median(Exam_Score, na.rm = TRUE),
SD = sd(Exam_Score, na.rm = TRUE),
N = n()
)
## # A tibble: 2 × 5
## Group Mean Median SD N
## <chr> <dbl> <dbl> <dbl> <int>
## 1 No Tutoring 71.9 71.5 7.68 40
## 2 Tutoring 78.4 78.7 7.18 40
Group Mean Median SD N
Step 5: Create Histograms for Each Group
hist(Dataset6.1$Exam_Score[Dataset6.1$Group == "Tutoring"],
main = "Histogram of Tutoring Scores",
xlab = "Value",
ylab = "Frequency",
col = "lightblue",
border = "black",
breaks = 10)
hist(Dataset6.1$Exam_Score[Dataset6.1$Group == "No Tutoring"],
main = "Histogram of No Tutoring Scores",
xlab = "Value",
ylab = "Frequency",
col = "lightgreen",
border = "black",
breaks = 10)
Step 6: Create Boxplots for Each Group
ggboxplot(Dataset6.1, x = "Group", y = "Exam_Score",
color = "Group",
palette = "jco",
add = "jitter")
Step 7: Shapiro-Wilk Test of Normality
shapiro.test(Dataset6.1$Exam_Score[Dataset6.1$Group == "Tutoring"])
##
## Shapiro-Wilk normality test
##
## data: Dataset6.1$Exam_Score[Dataset6.1$Group == "Tutoring"]
## W = 0.98859, p-value = 0.953
Shapiro-Wilk normality test
data: Dataset6.1\(Exam_Score[Dataset6.1\)Group == “Tutoring”] W = 0.98859, p-value = 0.953
shapiro.test(Dataset6.1$Exam_Score[Dataset6.1$Group == "No Tutoring"])
##
## Shapiro-Wilk normality test
##
## data: Dataset6.1$Exam_Score[Dataset6.1$Group == "No Tutoring"]
## W = 0.98791, p-value = 0.9398
Shapiro-Wilk normality test
data: Dataset6.1\(Exam_Score[Dataset6.1\)Group == “No Tutoring”] W = 0.98791, p-value = 0.9398
Step 8: Conduct Inferential Test
t.test(Exam_Score ~ Group, data = Dataset6.1, var.equal = TRUE)
##
## Two Sample t-test
##
## data: Exam_Score by Group
## t = -3.8593, df = 78, p-value = 0.000233
## alternative hypothesis: true difference in means between group No Tutoring and group Tutoring is not equal to 0
## 95 percent confidence interval:
## -9.724543 -3.105845
## sample estimates:
## mean in group No Tutoring mean in group Tutoring
## 71.94627 78.36147
Two Sample t-test
data: Exam_Score by Group t = -3.8593, df = 78, p-value = 0.000233 alternative hypothesis: true difference in means between group No Tutoring and group Tutoring is not equal to 0 95 percent confidence interval: -9.724543 -3.105845 sample estimates: mean in group No Tutoring 71.94627 mean in group Tutoring 78.3614
Step 9:Calculate the Effect Size Cohen’s D for Independent T-Test
cohens_d_result <- cohens_d(Exam_Score ~ Group, data = Dataset6.1, pooled_sd = TRUE)
print(cohens_d_result)
## Cohen's d | 95% CI
## --------------------------
## -0.86 | [-1.32, -0.40]
##
## - Estimated using pooled SD.
Cohen’s d -0.86
Step 10:Report the Results Tutoring (M = 71.9, SD = 7.18) was significantly different from No Tutoring (M = 71.94, SD = 7.68), t(78) = -3.86, p = 0.0002. The effect size was large (Cohen’s d = -0.86).