Statistik
30 cards from across every topic, each citing a source. Tap one to open it in the feed.
- "70% of lottery winners go broke" has no source. The truth surprises.
The 70% figure has circulated widely; the US foundation supposedly behind it said in 2018 it never did such research. …
- 23 people in a room, and two probably share a birthday.
With just 23 people, the chance that two share a birthday already exceeds 50 %. With 50 people it's 97 %. Intuition …
- A 99 percent accurate test, and you're still probably healthy.
A disease affects 1 in 10,000. The test detects it 99 percent of the time and gives 1 percent false alarms in healthy …
- A language's most common word appears twice as often as the second.
Zipf's law: rank words by frequency and the n-th is about 1/n as common as the first. In the Brown Corpus of English …
- A number without a plus-minus isn't a measurement, it's a claim.
Every measurement is uncertain, no matter how expensive the instrument. That is why labs worldwide agree: a result is …
- Cook for your family and GDP drops. Almost.
Gross domestic product only counts what is produced for money. If you cook yourself, care for your parents or fix your …
- Diagnosed earlier does not mean lived longer.
If a disease is normally found at 60 and someone dies at 65, the statistic records five years of survival. If screening …
- Florence Nightingale was, above all, a statistician.
In the Crimean War of 1854–56, ten times more British soldiers died of infection than of wounds in the military …
- How babies cut words out of a continuous sound stream.
Spoken language has no pauses between words. Babies solve this with statistics: they track which syllables tend to …
- How many languages does the world actually have?
Ethnologue counts about 7,100 living languages. The distribution is wildly uneven: roughly 40 percent are endangered …
- How many must take a treatment for one to benefit?
The Number Needed to Treat (NNT) answers exactly that. If a treatment cuts an event from 5 % to 4 %, the absolute …
- How statisticians turn thousands of prices into one inflation number.
Statistical offices record the prices of hundreds of goods and services every month, from bread to haircuts. Each …
- How to fit an entire economy into one formula.
The expenditure approach adds four items: private consumption, business investment, government spending and net …
- Ice cream sales and drownings rise together. Ice cream is innocent.
Two things occur together – that doesn't prove one causes the other. Often a third factor lies behind both: for ice …
- In 1990, one child in eleven died before their fifth birthday.
Globally, under-five mortality fell from 93 per 1,000 births (1990) to 37 per 1,000 (2022) – more than halved. Main …
- Insurance predicts not who is hit, only how many.
The law of large numbers says that the more often a random process repeats, the closer observed frequency sits to the …
- Nobody reached 30 in the Middle Ages – that's a maths error.
The low life expectancy of past eras is an average dragged down by high infant mortality. Among the English peerage it …
- One billionaire in the room is enough to move the average.
The arithmetic mean adds everything and divides; a single outlier drags it far upward. The median is the middle value …
- One healthy person in twenty falls outside the normal range.
A standard reference range is defined so that 95 percent of a healthy comparison group falls inside: 2.5 percent below …
- One hour of work a week and you aren't unemployed.
Under the International Labour Organization definition, which Eurostat also uses, anyone who worked at least one paid …
- Spain is just a tenth of the Spanish-speaking world.
Around 520 million people speak Spanish natively, more than English; only Mandarin has more. Spanish is official in 20 …
- The bullet holes nobody saw saved the bombers.
In the Second World War the US military wanted to armour planes where returning aircraft had the most bullet holes. …
- The first law of geography fits in one sentence.
Waldo Tobler wrote in a 1970 paper on Detroit's growth: "Everything is related to everything else, but near things are …
- The two-quarter rule is a rule of thumb, not a definition.
Popularly, an economy is in recession when real GDP shrinks for two consecutive quarters. In the United States, though …
- Three doors, one car: why switching doubles your odds.
A car sits behind one of three doors. You pick one; the host, who knows where the car is, opens another door showing a …
- Why a record is almost always followed by a weaker result.
Every measurement is skill plus chance. An extreme result usually included extreme luck, and luck doesn't repeat. The …
- Why country comparisons in absolute numbers almost always mislead.
A country with 1.4 billion people tops nearly every total: cars, emissions, accidents. That says little about any …
- Why vitamin pills work in observations but not in trials.
People who voluntarily take vitamins usually also exercise more, smoke less and see doctors more often. In …
- “My grandpa smoked and lived to 95” is not an argument.
You only hear from the smokers who grew old – the others no longer tell stories. That's survivorship bias: you see only …
- “Risk cut by 50 %” can mean 1 person in 1,000.
Relative risk compares groups: if a disease drops from 2 to 1 per 1,000, that's “50 % less”. In absolute terms it's 0.1 …