One of the key assumptions of regression is that the variance of the errors is constant across observations. Correcting for heteroscedasticity improves the efficiency of the estimates. If you had a ...

Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...

Discover how efficiency variance reveals the gap between expected and actual inputs in production and its impact on labor, materials, and costs.

Stock's historical variance measures its return stability over time. Higher variance indicates greater return unpredictability and risk. Calculate variance using Excel to simplify the process for ...

Labor price variance, or direct labor rate variance, measures the difference between the budgeted hourly rate and the actual rate you pay direct labor workers who directly manufacture your products.

Neurons transmit information with sequences of action potentials. These responses are variable—repeated measurements under identical experimental conditions give different spike trains—but the origins ...