Time series forecasting of daily TransJakarta passenger counts (Jan 2023 - Jun 2024) using an Autoregressive Distributed Lag (ARDL) model with route adjustment as an external variable. Covers optimal lag selection (AIC), diagnostic tests, train/test evaluation with MAPE, and multistep forecasting.

One-way ANOVA for a completely randomized design in R, comparing chlorophyll content in cassava, spinach, and lettuce leaves. Builds the linear model in matrix form (X’X, X’y, reparameterization), computes the ANOVA table manually and checks it against aov(), then tests normality and homogeneity of variance.

Analysis of a two-factor experiment in a randomized block design using R. Tests the main effects of variety and fertilizer, their interaction, and the block effect with ANOVA, and visualizes the interaction with an interaction plot.

Multiple linear regression on provincial data (34 provinces) to identify factors affecting the democracy index, such as press freedom, number of CSOs, HDI, and public information openness. Covers multicollinearity check (VIF), outlier, leverage and influence diagnostics, classical assumption tests, and model selection (forward, backward, stepwise, best subsets).

Exploratory data analysis of earthquake depth in R. Compares the standard boxplot with the adjusted boxplot (medcouple-based) for skewed data, and checks the distribution with a histogram, density curve, and Shapiro-Wilk test.

Practice in data manipulation with R’s tidyverse, using the built-in quakes dataset (1,000 earthquakes near Fiji). Covers filter, select, group_by with summarize, arrange, and mutate to subset, summarize, and create new variables.

Introductory practice in R data wrangling using the built-in iris dataset (150 flowers, 3 species). Covers glimpse, filter, select, group by with summarize, arrange, and mutate, plus chaining steps with the pipe operator.