For each variable, determine whether it is best thought of as discrete or continuous.
VariableDiscreteContinuous(a) The time that a student in Introduction to Calculus takes to complete a midterm exam
(b) The number of students, in a class of
35
, who improve their score from the first midterm to the second midterm
(c) The mass of the solid impurities per milliliter of Los Angeles tap water
(d) The intensity of a
1000
-
Hz
tone judged by a participant to be "equally as loud as" a
500
-
Hz
tone of
50
decibels