Daniel Nkwocha

I am an Electrical Engineering and analyst with several years of experience across statistical analysis, data visualisation, and reproducible reporting. I cover the full analytical workflow, from raw data ingestion and cleaning through to formal modelling, professional visualisation, and polished final outputs that are documented, reproducible, and clearly interpreted.

I specialise in the following areas within R and RStudio:

Data cleaning, manipulation, and wrangling using dplyr, tidyr, stringr, lubridate, and janitor. I handle missing values, outliers, inconsistent formatting, and structural data problems, and document all transformations so every step is fully traceable.

Hypothesis testing with assumption verification covering normality, homoscedasticity, and independence checks before test selection. Tests include t-tests, ANOVA with post-hoc comparisons, Mann-Whitney U, Wilcoxon, Kruskal-Wallis, chi-squared, Fisher's exact, and Pearson and Spearman correlation. All results include test statistics, p-values, confidence intervals, and effect sizes. Where multiple tests are run I apply Bonferroni or Benjamini-Hochberg correction to keep results statistically honest.

Power analysis, a priori to establish required sample sizes and post hoc to evaluate study sensitivity.

Statistical modelling including linear and logistic regression with full residual diagnostics, Cook's distance, leverage, and VIF checks for multicollinearity.

Data visualisation using ggplot2 with attention to chart type, colour, annotation, and theme. I produce scatter plots, bar charts, line graphs, box plots, heatmaps, and multi-panel figures using patchwork.

All code is clean, commented, and fully reproducible. Client data is handled with complete confidentiality and not retained beyond the project. I ask clarifying questions before starting, provide updates at key stages, flag issues early, and agree scope upfront.