Branch 08 · free, no sign-up
Statistics Calculators
Statistics is where maths stops giving one right answer and starts describing how confident you can be. The arithmetic is simple; choosing the right measure is the part that matters.
Every calculator in this branch is checked by a mathematician before it goes live.
- 4, 8, 9, 11 the data set
- (4 + 8 + 9 + 11) ÷ 4 sum the values, divide by how many
- 32 ÷ 4 = 8 the mean
Calculators
All 9 statistics calculators, by topic
describe the data, then reason about chance
Descriptive
Probability
Distributions
Where this sits
What comes before statistics
each topic assumes the one to its left
Stuck part way through? Start at the leftmost topic you are not sure about — everything to the right depends on it.
Knowledge base
Read the reasoning, not just the answer
one article per question a teacher would answer
Questions
Asked often enough to answer here
the ones that change how you work, not trivia
When is the median better than the mean?
When the data has outliers. One very large salary drags the mean upward while the median stays where most people actually are — which is why income is almost always reported as a median.
Why divide by n−1 for a sample?
Dividing by n underestimates the spread, because the sample mean sits closer to the sample than the true mean does. Using n−1 corrects that bias.
Does a low probability mean something will not happen?
No. It means it happens rarely across many trials. A one-in-a-thousand event is close to certain somewhere in a million trials.
Nearby
Branches that touch this one
linked because the maths overlaps, not because it fills space