Problem: Find the mode of the data set: 4, 7, 2, 7, 9, 2, 7, 3.
Step 1: Count how many times each value appears.
2→2 times,3→1,4→1,7→3,9→1
Step 2: Identify the value with the highest frequency. The number 7 appears 3 times, which is more than any other value.
Answer: The mode is 7.
Why It Matters
The mode is the only measure of central tendency that works for non-numerical (categorical) data — for instance, you can find the most popular color in a survey, but you cannot compute the mean of colors. It is also useful for identifying the most common outcome in a data set, which matters in fields like retail (best-selling product) and medicine (most frequent symptom).
Common Mistakes
Mistake: Assuming every data set has exactly one mode.
Correction: A data set can be bimodal (two modes) or multimodal (more than two). For example, in {1, 2, 2, 3, 3}, both 2 and 3 are modes. If all values occur equally often, there is no mode.
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