Learn sum of squared errors SSE in regression, how it measures prediction error, and its role in ordinary least squares and CFA quantitative methods.

Learn sum of squared residuals in regression, how it measures model errors, and its role in ordinary least squares and CFA quantitative methods.

Learn R squared in regression, how it measures explanatory power, and how to interpret coefficient of determination in CFA quantitative methods and finance.

Learn what probability sampling is, why randomness allows statistical inference, and how simple random, stratified, and cluster sampling differ for CFA quantitative methods.

Understand non probability sampling, its types such as convenience and quota sampling, and why lack of randomness limits statistical inference in research and CFA exams.

Understand what the mean really represents in statistics and finance. Learn how the mean is used, why it matters for risk analysis, and when it can be misleading.

Mean Absolute Deviation explained intuitively. Learn how MAD measures average dispersion, how it differs from variance and standard deviation, and why it matters in CFA and FRM exams.