Randomized test: refers to a test that has multiple possible results under the same conditions and can be repeated; although all possible results of the test are known in advance, the results of each specific test cannot be predicted. Which of the following are randomized trials? ['Test of heating a pot of freshwater to boiling and observing its state change.', 'Test of installing a positioning device on a lion to understand its living habits.', 'Impact test to check the safety performance of a new car.', 'Trial of a coin to observe the number of side ups with numbers.']