I would consider a load test on an LDO a DC test, meaning static voltages and currents.
So my test could for example be:
- apply input voltage of 5V, 6 V and 7 V
- for each input voltage load the output with 1 mA, 10 mA and 100 mA and measure the output voltage and input current.
For that I would use current and voltage meters, an oscilloscope isn't really needed. Still, you could use an oscilloscope as well if that is all you have.
The min, max, mean, rms and peak-peak measurements on an oscilloscope are intended for AC signals. For example a 50 Hz sinewave could have:
- a maximum of +1 V
- a minimum of -1 V
- a mean voltage of 0 V (there is no DC present)
- an RMS value of 0.7 V
- a peak-peak value of 2 V
All of these, except the mean value, are not very useful for a DC voltage or current.
On the oscilloscope you could select mean but it is not really needed especially if the voltage isn't that noisy as then the standard value (no min, max etc.) is good enough already.
Things are different if you want to do a dynamic load test so for example applying a sinewave on top of the DC input voltage of the LDO. Then the scope's min, max etc. settings can become more important depending on what you want to measure.