Why do theoretical and practical value differ for BJT amplifier experiment?

Theoretical and practical values in a BJT amplifier experiment often differ due to ideal assumptions in theoretical calculations, such as constant temperature, perfect components, and neglecting parasitic effects. In practice, variations in transistor parameters, non-ideal behaviors, and external factors like noise and power supply fluctuations can lead to discrepancies. Additionally, measurement inaccuracies and limitations in circuit design can further contribute to the differences observed between theoretical predictions and practical outcomes.