Various online resources (online sources, text books) are freely available on internet.
There are so many online courses that you might get overwhelmed bu the sheer numbers.
- Probability and Statistics in Data Science using Python by UC SanDiego
- Data Science: Probability by Harvard
- Statistics and R by Harvard
- Statistics and Data Science by MITx
- Introduction to Probability by Harvardx
- Methods and Statistics in Social Sciences Specialization by University of Amsterdam on Coursera
- Quantitative Methods
- Qualitative Research Methods
- Basic Statistics by University of Amsterdam on Coursera
- Inferential Statistics by University of Amsterdam on Coursera
- Improving your statistical inferences
- Bayesian Statistics: From Concept to Data Analysis by University of California on Coursera
- Bayesian Statistics: Techniques and Models by University of California on Coursera
- Statistical Inference by John Hopkins University on Coursera
- An Intuitive Introduction to Probability by University of Zurich on Coursera
- Statistics with R Specialization by Duke University on Coursera
- Introduction to Probability and Data by Duke University on Coursera
- Inferential Statistics by Duke University on Coursera
- Linear Regression and Modeling by Duke University on Coursera
- Bayesian Statistics by Duke University on Coursera
- Regression Modeling in Practice by Wesleyan University
- Advanced Linear Models for Data Science 1: Least Squares
- Advanced Linear Models for Data Science 2: Statistical Linear Models
- Experimentation for Improvement by McMaster University on Coursera
- Practical Time Series Analysis by the state university of New York on Coursera
- Probability and Statistics: To p or not to p? by University of London on Coursera
- Causal Inference by Columbia University on Coursera
- Econometrics: Methods and Applications by Erasmus University Rotterdam on Coursera.
- Fundamentals of Quantitative Modeling by University of Pennsylvania on Coursera