Gemiddelde, Mediaan en Modus Calculator

An average calculator computes the four fundamental descriptive statistics for any set of numbers: the mean (the sum of all values divided by the count), the median (the middle value in the sorted dataset), the mode (the most frequently occurring value), and the range (the difference between the maximum and minimum values). Together, these four statistics describe both the center and spread of any dataset — the foundation of quantitative analysis in science, business, education, and everyday decision-making.

The arithmetic mean is the most widely used summary statistic in human history — from ancient grain distributions to modern machine learning. But it is also the most frequently misapplied. Income inequality, housing market trends, sports performance analysis, and medical study results all suffer from misreported or misunderstood averages. A single outlier can move the mean dramatically while the median stays stable. Understanding which average to use — and what each one actually tells you — is the difference between insight and misleading oversimplification.

This calculator handles datasets of any size, computes all four statistics simultaneously, and presents the results with clarity. Whether you are analyzing student test scores, averaging monthly sales figures, finding the central tendency of measurement data, or understanding what 'typical' means for any numerical dataset, these four statistics together provide a complete picture that no single number can capture alone.

Example 1 — Student test scores: Scores: 72, 85, 91, 68, 95, 72, 88, 60 n = 8. Sum = 631. Mean = 631 / 8 = 78.9 Sorted: 60, 68, 72, 72, 85, 88, 91, 95 Median = (72 + 85) / 2 = 78.5 (average of 4th and 5th values) Mode = 72 (appears twice, all others once) Range = 95 − 60 = 35

Example 2 — Monthly sales ($thousands): 42, 38, 55, 61, 47, 38, 210, 44 Mean = 535 / 8 = 66.9 (inflated by the outlier month of 210) Median = (44 + 47) / 2 = 45.5 (robust, ignores the outlier) Mode = 38 (appears twice) Range = 210 − 38 = 172 Conclusion: median (45.5) better represents 'typical' monthly sales than mean (66.9).

Example 3 — Temperature readings (°C): 21, 22, 21, 23, 21, 22, 24, 22 Mean = 176 / 8 = 22.0 Median = (22 + 22) / 2 = 22.0 Mode = 21 and 22 (bimodal — each appears 3 times) Range = 24 − 21 = 3

Example 4 — Household incomes in a neighborhood ($): 45000, 52000, 48000, 61000, 55000, 1200000 Mean = 1,461,000 / 6 = 243,500 (badly distorted by the millionaire) Median = (52,000 + 55,000) / 2 = 53,500 (accurate representation) Range = 1,200,000 − 45,000 = 1,155,000

Descriptive statistics — mean, median, mode, and range — are the foundation of data literacy in the modern world. Every field that involves numbers uses these statistics: medicine (average clinical trial outcomes), finance (average portfolio returns), education (average test scores), sports (batting averages, player efficiency ratings), manufacturing (average defect rates), and public policy (median income, average unemployment). The ability to compute and correctly interpret these numbers is not optional for informed decision-making — it is essential.

The most consequential real-world application of the mean-vs-median distinction is income and wealth reporting. When economists report that 'average household income rose by 5%,' that statement can be true while median household income fell — if the gains accrued entirely to the top percentile. This is not a hypothetical: U.S. income data consistently shows mean income significantly above median income, with the gap widening over the past 40 years. Voters, policymakers, and journalists who cannot distinguish these measures are systematically misled about economic reality.

In scientific research, the choice between mean and median affects study conclusions. Clinical trials often report both because physiological measurements frequently have non-normal distributions. Drug efficacy studies that report only the mean can obscure the fact that a small subset of patients responded dramatically while the majority showed no effect — a bimodal distribution where the mean falls between the two peaks, representing almost no one in the study. Understanding when to use each measure — and recognizing when a single summary statistic is insufficient to characterize a dataset — is the core of statistical literacy.

This calculator computes the four basic descriptive statistics: mean, median, mode, and range. It does not compute more advanced statistics such as standard deviation, variance, interquartile range (IQR), skewness, kurtosis, or percentiles. For datasets requiring these measures — scientific research, quality control analysis, financial risk modeling — a full statistical software package (R, Python with NumPy/SciPy, or a spreadsheet) provides the complete toolkit.

The mean computed here is the arithmetic mean — the most common type. Other types of means exist for specific applications: the geometric mean (used for compounding rates, like average investment returns over multiple years), the harmonic mean (used for averaging rates, like average speed over a journey), and the weighted mean (used when values have different importance). If your application requires one of these alternative means, the arithmetic mean from this calculator will produce incorrect results.

For very large or very small datasets, the presentation of mode may be simplified. In continuous numerical data (measurements with many decimal places), every value is likely unique — the mode is technically undefined or uninformative. Mode is most useful for discrete data where repetition is meaningful (test scores, survey ratings, count data). For continuous measurements, consider rounding values to a meaningful precision before computing mode, or use the median as the primary central tendency measure.