# Create sample biological dataset
data <- data.frame(
  Hemoglobin = c(12.5,13.2,11.8,14.0,13.5,14.2,11.5,14.8,12.9,14.1)
)

x <- data$Hemoglobin

# -----------------------------
# Basic Descriptive Statistics
# -----------------------------

# Mean
mean(x)

# Median
median(x)

# Mode (custom function)
mode_func <- function(x) {
  ux <- unique(x)
  ux[which.max(tabulate(match(x, ux)))]
}
mode_func(x)

# Minimum
min(x)

# Maximum
max(x)

# Range
range(x)

# Sum
sum(x)

# Count (Sample Size)
length(x)

# -----------------------------
# Measures of Dispersion
# -----------------------------

# Variance
var(x)

# Standard Deviation
sd(x)

# Interquartile Range (IQR)
IQR(x)

# Quartiles
quantile(x)

# -----------------------------
# Position Measures
# -----------------------------

# Percentiles (example: 25%, 50%, 75%)
quantile(x, probs = c(0.25, 0.5, 0.75))

# Deciles (10%, 20%, ..., 90%)
quantile(x, probs = seq(0.1, 0.9, by = 0.1))

# -----------------------------
# Shape Measures
# -----------------------------

# Install package (only first time)
install.packages("moments")

# Load package
library(moments)

# Skewness
skewness(x)

# Kurtosis
kurtosis(x)