Question

for each variable, determine whether it is best thought of as discrete or continuous.
variable\tdiscrete\tcontinuous
(a) the total amount of time that customers spend this week listening to telephone \hold\ music while calling 1-800-parcels\t○\t●
(b) the time that a student in introduction to calculus takes to complete a midterm exam\t●\t○
(c) the body weight of a preschool child\t○\t●
(d) the number of damaged chromosomes on a petri dish following irradiation\t○\t●

Explanation:

• (a) Time is a continuous variable as it can take any value within a range (e.g., 10.5 minutes, 15.23 minutes).
• (b) Time to complete an exam is continuous. It can be, say, 90.5 minutes, and there are an infinite number of possible values between any two - time points.
• (c) Body weight is continuous. A child's weight can be 15.3 kg, 16.78 kg etc., and it can take on an uncountable number of values within a reasonable range.
• (d) The number of damaged chromosomes is discrete. You can count the number of chromosomes (e.g., 1, 2, 3...), and there are no values in between whole numbers for this count.

Answer:

(a) Continuous, (b) Continuous, (c) Continuous, (d) Discrete