According to scribbr.com and en.wikipedia.org, there are a few examples of a quantitative study using UN data:
Global Health: Analyze data from the World Health Organization (WHO) to study the correlation between healthcare spending and life expectancy across different countries.
Climate Change: Use data from the Intergovernmental Panel on Climate Change (IPCC) to investigate the relationship between carbon dioxide emissions and average temperature rise in various regions.
Education: Examine UNESCO’s education statistics to understand the impact of education level on gender equality in different countries.
Economic Development: Utilize data from the International Monetary Fund (IMF) or World Bank to study the effect of foreign direct investment on economic growth.
Peace and Security: Analyze data from the UN Peacekeeping Statistics to assess the effectiveness of peacekeeping missions in reducing conflict.
Remember, the key to a successful quantitative study is to have a clear research question, well-defined data collection and analysis methodology, and a rigorous approach to interpreting the results.