Which of the following is NOT a discrete random variable?
A. Number of refrigerator sell each day
B. Height of dragon fruit as measured each day
C. Number of students late in going to school each day
D. Number of people went to the doctor from Monday to Friday
The correct answer and explanation is :
The correct answer is B. Height of dragon fruit as measured each day.
Explanation:
To understand why option B is the correct answer, let’s break down the concept of discrete and continuous random variables.
A discrete random variable is one that takes on countable values. These variables represent quantities that can be listed, counted, or assigned a specific value. In contrast, a continuous random variable can take on an infinite number of values within a given range and is typically measured rather than counted.
Now, let’s analyze each option:
A. Number of refrigerators sold each day
This is a discrete random variable. The number of refrigerators sold in a day can only be a whole number (e.g., 0, 1, 2, 3,…). It is countable and finite, making it a discrete random variable.
B. Height of dragon fruit as measured each day
This is a continuous random variable. The height of the dragon fruit can take on an infinite number of possible values, including decimals, within a certain range. Since height is measured and can have a fraction or decimal component (e.g., 10.3 cm, 10.4 cm, etc.), it is continuous, not discrete.
C. Number of students late in going to school each day
This is a discrete random variable. The number of students who are late is countable (e.g., 0, 1, 2, 3,…). It is a finite count and cannot take non-integer values.
D. Number of people who went to the doctor from Monday to Friday
This is a discrete random variable. The number of people who visit the doctor within a specific time frame (e.g., 1, 2, 3,… people) is countable and finite.
Thus, the height of the dragon fruit (option B) is a continuous variable, and the others are discrete variables because they can only take specific, countable values.
Key Difference:
- Discrete variables: Countable values (e.g., number of people, number of items sold).
- Continuous variables: Measurable and can take an infinite number of values within a range (e.g., height, weight, temperature).