I-Calculator yesikhathi sokwethemba
Yakha isikhala sokwethemba kwesilinganiso sesampula sesilinganiso, SD nesayizi.
Iziphetho zivuselelwa uma ubhala.
Malunga nale khadi
A confidence interval gives a range that is likely to contain the true population mean, estimated from a sample. Instead of a single best guess it reports a band together with a confidence level that says how often such bands capture the true value.
This calculator uses the z-interval: mean ± z*·(σ / √n), where z* is the standard-normal critical value for your chosen confidence level (1.645 for 90%, 1.96 for 95%, 2.576 for 99%) and σ / √n is the standard error. It reports the bounds, the margin of error and the standard error, and a table shows the interval at the 90%, 95% and 99% levels so you can see how the range widens as you demand more confidence.
Worked example: a sample mean of 100 with a standard deviation of 15 and 50 observations has a standard error of 15 ÷ √50 ≈ 2.12. At 95% confidence the margin is 1.96 × 2.12 ≈ 4.16, giving an interval of about 95.84 to 104.16. The z-interval suits large samples (roughly n ≥ 30) or a known population standard deviation; for small samples use a t-interval instead.
Imibuzo ebuzwa kaningi
Yini okushoyo i-95% confidence interval?
Kuthi uma uphinde uthathe isampula izikhathi eziningi futhi ukwakha isikhala ngasikhathi ngasinye, cishe i-95% yale miphakathi izofaka isilinganiso sabantu esingokoqobo. Kuthi akusho ukuthi kukhona i-95% ingozi yokuthi isilinganiso sikhona kulesithuba esisodwa esikhethekile.
Ngabe kufanele ngisebenzise i-t-interval endaweni?
Sebenzisa i-t-interval uma isifanekiso sincane (ingaphansi kuka-30) futhi ukuhlukana okujwayelekile komphakathi akuziwa. U-t-distribution unezinhlangothi ezinzima, unikeza isikhala esibanzi, esiwusizo kakhulu kune-z-based.
Yini ibanga lephutha esikhathini sokwethemba?
I-margin yephutha yingxenye yobubanzi besikhathi, z*·(σ / √n). Ungeza futhi ususe kusuka kusampula okusho ukufinyelela ezingeni eliphezulu nelisephansi, ngakho-ke i-margin encane isho ukulinganiselwa okucacile.
Ngingenza kanjani isikhala sokwethemba esincane?
Thola isibonisi esikhulu, njengoba ububanzi buncane nge-square root ye-n, noma uthathe isilinganiso esiphansi sokuzithemba. Ukuncipha koshintsho kudatha yakho kwenza kube nzima ukuhlukanisa. Ukuphindaphinda ubukhulu besampula kuncane kakhulu kushiya ububanzi.
Ingabe izinga eliphakeme lokuthembela likwenza isikhala sibanzi?
Yebo. Ukucela ukuthembela okuningi kusetshenziswa inani elibalulekile elikhulu z *, ngakho-ke i-99% yesikhathi esiphakathi sibanzi kuna-95% sesikhathi esiphakathi esikhiwa kusuka ku-data efanayo. Kuhlala kukhona ukuhweba phakathi kokuthembela nokunemba.
Yini iphutha elijwayelekile?
Iphutha elijwayelekile liyiphutha elijwayelekile elihlukaniswe ngesisekelo esiyisikwere sesampula (σ / √n). Lilinganisela ukuthi isampula lizoshintsha kanjani kusuka kumklamo kuya kumklamo, futhi liyisakhiwo se-block se-margin yephutha.
API — sebenzisa le calculator kusuka kukhodi
Nquma le calculator njenge JSON evulekile yendawo yokuqeda - akukho isithonjana esidingekayo. Thumela amaxabiso endawo ngezansi njengezilungiselelo zombuzo noma i-JSON. Noma yini ongayishiya isebenzisa iphutha elifanayo elifakwe ngaphambili lekhasi; ipharamitha engaziwa yi-400, ayikho i-zero emnyama. Funda i-API egcwele →
Ingxenye yendawo
GET https://calculator.free/api/v1/confidence-interval/curl
curl "https://calculator.free/api/v1/confidence-interval/?mean=100&sd=15&n=50&conf=1.96"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/confidence-interval/?" + new URLSearchParams({
"mean": "100",
"sd": "15",
"n": "50",
"conf": "1.96"
}));
const data = await r.json();
console.log(data.results);Izibalo ziyisilinganiso esisetshenziswa ukuqondisa kuphela, hhayi ukucebisa ngezimali, ukwelashwa noma ukukhokha.