$Which\; of\; the\; following\; is\; a\; discrete\; random\; variable?$

• A. $The\; time\; it\; takes\; for\; a\; computer\; to\; complete\; a\; calculation$
• B. $The\; weight\; of\; a\; randomly\; chosen\; apple$
• C. $The\; number\; of\; heads\; obtained\; when\; flipping\; a\; coin\; three\; times$
• D. $The\; exact\; height\; of\; a\; randomly\; selected\; student\; in\; centimeters$

Answer: (C)

Verified step by step guidance

1. Understand the definition of a discrete random variable: it is a variable that can take on a countable number of distinct values, often integers, such as counts of occurrences.
2. Analyze each option to determine if the variable is discrete or continuous:
3. 1. The time it takes for a computer to complete a calculation is typically measured on a continuous scale (e.g., seconds, milliseconds), so it is a continuous random variable.
4. 2. The weight of a randomly chosen apple can take any value within a range and is measured continuously, so it is a continuous random variable.
5. 3. The number of heads obtained when flipping a coin three times can only be 0, 1, 2, or 3, which are countable values, making it a discrete random variable.