Which of the following is an example of a discrete variable?

Which of the following is an example of a discrete variable?

• A. Height in centimeters
• B. Temperature in Celsius
• C. Number of siblings
• D. Blood type

Answer: (C)

The key idea here is the distinction between discrete and continuous variables. A discrete variable takes separate, countable values—usually whole numbers—because you’re counting items. The number of siblings is a count of people in the family and can only be whole numbers like 0, 1, 2, and so on, so it’s discrete. Height in centimeters is measured and, in principle, can be any real value within a range (you could have 170.5 cm, 170.25 cm, etc.), making it continuous. Temperature in Celsius is also a measurement that can take many fractional values, so it’s continuous as well. Blood type is a category, a qualitative label rather than a numeric amount, so it’s not a numerical discrete variable.

The key idea here is the distinction between discrete and continuous variables. A discrete variable takes separate, countable values—usually whole numbers—because you’re counting items. The number of siblings is a count of people in the family and can only be whole numbers like 0, 1, 2, and so on, so it’s discrete. Height in centimeters is measured and, in principle, can be any real value within a range (you could have 170.5 cm, 170.25 cm, etc.), making it continuous. Temperature in Celsius is also a measurement that can take many fractional values, so it’s continuous as well. Blood type is a category, a qualitative label rather than a numeric amount, so it’s not a numerical discrete variable.