Statistics and weighted average are both ways of summarizing numbers, but they answer different questions. The statistics calculator treats every value as one observation and reports how the data are distributed — where they center and how widely they spread. The weighted average calculator starts from the idea that some values matter more than others and produces a single mean in which each value counts in proportion to its weight.
What each calculator does
The statistics calculator accepts 1 to 100 numeric values and computes the mean, median, mode, range, sample variance, sample standard deviation, sample size, sum, minimum, and maximum. It uses sample variance and sample standard deviation, dividing squared deviations by n − 1 rather than n. The median is the middle sorted value (or the average of the two middle values for an even count), and the mode is any value repeating at least twice. Statistics display with four decimals. With a single value, variance and standard deviation are reported as not available because n − 1 would be zero. An Average percentages preset handles 2 to 5 equally weighted percentage values with two-decimal percent formatting.
The weighted average calculator takes up to 100 value-and-weight rows and computes Σ(value × weight) ÷ Σ(weight). Weights are expected to be zero or positive; a zero-weight row contributes nothing, and the input is invalid if the total weight is zero. Only the final quotient is rounded, to two decimals. In the calculator’s checked example, values 90, 85, and 95 with weights 20, 50, and 30 produce weighted products 1,800, 4,250, and 2,850, a total weight of 100, and a weighted average of 89.
Side-by-side
| Statistics calculator | Weighted average calculator | |
|---|---|---|
| Inputs | 1–100 equally weighted values | Up to 100 value + weight rows |
| Primary output | Mean, plus median, mode, range, variance, standard deviation, sum, min, max | One weighted mean |
| Treatment of values | Each value counts once | Each value counts in proportion to its weight |
| Spread | Sample variance and standard deviation included | Not applicable — no spread measures |
| Percentage mode | Average percentages preset (2–5 equally weighted values) | Weights can be percentages, points, credits, or hours |
| Display precision | Four decimals (percent preset: two) | Two decimals on the final quotient |
When to use which
Use the statistics calculator when you need to understand a distribution: does the mean represent a typical observation, or do outliers pull it away? Check the median against the mean, and look at the range and standard deviation. That is the tool for raw scores, lab measurements, or times where every point is one observation.
Use the weighted average calculator when the entries have different importance and the plain mean would mislead. A one-credit quiz and a four-credit lab are not equal observations; a 60-percent portfolio holding should influence a return more than a 5-percent one; a group mean based on 800 people should count more than a mean based on 20. The classic mistake both pages warn about: averaging already-averaged numbers without weighting by their denominators. If two class sections average 70 across 10 students and 90 across 40, the combined average is not 80.
Limits and disclaimer
The statistics calculator’s spread measures are sample-based (division by n − 1), which is standard for a sample drawn from a larger process but different from population variance. Neither tool removes outliers or missing values automatically, and both reject blank or nonnumeric inputs. A weighted average with nonnegative weights stays between the smallest and largest values; results outside that range signal negative weights or entry errors. Both pages are educational arithmetic tools, not statistical software — use them for small, careful checks rather than formal analysis.