Question

for each variable, determine whether it is best thought of as discrete or continuous.
variable
(a) the number of damaged chromosomes on a petri dish following irradiation
(b) the total amount of time that customers spend this week listening to telephone \hold\ music while calling 1-800-parcels
(c) the number of typographical errors in an edition of the metropolitan newspaper
(d) the lifetime, in hours, of a 100-watt light bulb manufactured by bingley corporation
discrete
(a)
(b)
(c)
(d)
continuous
(a)
(b)
(c)
(d)

Explanation:

• (a) The number of damaged chromosomes is a countable quantity (e.g., 0, 1, 2,...). So, it is a discrete variable.
• (b) The total amount of time is a measurement that can take any value within an interval (e.g., 10.5 minutes, 15.23 minutes). So, it is a continuous variable.
• (c) The number of typographical errors is a countable quantity (e.g., 0, 1, 2,...). So, it is a discrete variable.
• (d) The lifetime of a light - bulb is a measurement (e.g., 1000.5 hours, 1200.3 hours). So, it is a continuous variable.

Answer:

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