Question

Which of the following variables are best thought of as continuous, which discrete? Indicate your choice for each by checking the appropriate column.
Variable   Discrete   Continuous
(a) The number of personal telephone calls made tomorrow at Bingley Corporation  

(b) The number of defective compact discs in a batch of 500 discs  

(c) The time that a student in Calculus 101 takes to complete a midterm exam  

(d) The actual length of a roll of plastic wrap advertised to be 30 feet long  

Answer 1

Continuous variable can take any numerical value whereas discrete variable only takes non decimal values

(A) number of personal telephone calls is a discrete variable as the number of calls can never be a decimal number. So, it is a discrete variable

(B)  number of defective compact discs in a batch of 500 discs is a discrete variable as the number of defective must be a non decimal number. So, it is a discrete variable

(C) time that a student in Calculus 101 takes to complete a midterm exam is a continuous variable as time can be expressed in decimal format. So, it is a continuous variable

(D) actual length of a roll of plastic wrap advertised to be 30 feet long is a continuous variable as we can express the actual length as 30.2 feet or 29.8 feet. So, it is a continuous variable