Which of the following is a common type of non-invasive monitoring equipment?

The electrocardiogram (ECG) machine is a common type of non-invasive monitoring equipment, as it is designed to record the electrical activity of the heart through electrodes placed on the skin. This method allows healthcare professionals to assess the heart's rhythm, detect any abnormalities, and monitor the heart's function without the need for invasive procedures.

In contrast, other equipment listed may have different applications or methods of operation. For instance, a magnetic resonance imaging machine, while a vital diagnostic tool, is primarily used for imaging rather than continuous monitoring. A blood gas analyzer, while essential for assessing respiratory function and metabolic status, typically involves taking blood samples, making it an invasive procedure. A surgical table, on the other hand, is a piece of equipment used for positioning patients during surgical procedures rather than for monitoring physiological parameters. Thus, the electrocardiogram machine stands out as a standard non-invasive monitoring tool in clinical settings.