When a function is given in the form if a relation. i.e. ordered pairs.
When the function is given in the form of ordered pairs then the set of first elements i.e. x-coordinates of all ordered pairs forms domain while the set of second elements i.e. y-coordinate of all ordered pair is called range.
Rejection of aspirin argument is more dangerous because the incorrect dosage of aspirin may cause more severe adverse reactions than the incorrect dosage of vitamin C. It would be prudent to use a lower level of significance to test the aspirin argument.