平均・中央値・最頻値・範囲の計算機
任意の数値リストの平均値、中央値、最頻値、範囲を即時計算します。
とは an Average?
An average (or arithmetic mean) is the sum of a set of numbers divided by the count of numbers in the set. It is the most common measure of central tendency and gives a single value that represents the "center" of the data.
For example, the average of 2, 4, 6, 8, 10 is (2+4+6+8+10)/5 = 30/5 = 6.
Our calculator also computes the median (middle value when sorted), mode (most frequent value), and range (max − min), giving you a complete statistical summary.
Mean vs Median vs Mode
- Mean: Sum ÷ count. Best for symmetric data without outliers.
- Median: The middle value in sorted order. Resistant to outliers — preferred for income, housing prices, etc.
- Mode: The value that appears most often. Useful for categorical data or finding the most common outcome.
- Range: Max − min. Measures the spread of the data.
When your data has outliers, the median is usually a better summary than the mean. For example, if nine people earn $30,000 and one earns $1,000,000, the mean is $127,000 — which doesn't reflect anyone's actual salary — while the median is $30,000.
このツールの使い方
Enter your numbers separated by commas in the input field. For example: 5, 10, 15, 20, 25. The calculator will instantly compute the mean, median, mode, range, count, and sum. You can enter integers or decimals, positive or negative numbers.
Common uses include: calculating student grade averages, summarizing survey results, analyzing sports statistics, and performing quick data checks in science and finance.
よくある質問
とは the difference between mean and average?
The terms 'mean' and 'average' are often used interchangeably. In everyday use, 'average' usually refers to the arithmetic mean — the sum divided by the count. Technically, 'average' is a broader term that can include mean, median, and mode.
What if all numbers appear the same number of times?
If every number in the dataset appears exactly once (or an equal number of times), there is no single mode — every value is a mode. In practice, statisticians say the data has no mode or is multimodal.
How do I calculate a weighted average?
A weighted average multiplies each value by its weight, sums the products, and divides by the total weight. For example, if a test is worth 60% and homework 40%, and you scored 80 and 90 respectively: (80×0.6 + 90×0.4) = 48 + 36 = 84.