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Malunga nale Calculator
This sample size calculator finds how many people you need to survey for a chosen margin of error and confidence level — the planning step before you run a poll or study. It uses the standard formula n = z²·p(1 − p) / e², where z is the critical value for the confidence level, p the expected proportion and e the target margin of error as a decimal.
When you supply a total population size it also applies a finite-population correction, n = n₀ / (1 + (n₀ − 1)/N), which lowers the required sample when you are surveying a large fraction of a small group. A table shows the sample needed at several common margins of error, and the result is always rounded up because you cannot survey a fraction of a person.
Worked example: for a 5% margin at 95% confidence with an unknown proportion (p = 0.5), n = 1.96² × 0.5 × 0.5 ÷ 0.05² = 3.8416 × 0.25 ÷ 0.0025 ≈ 384.16, so you need 385 respondents. Tightening the margin to 3% pushes that to about 1,068. The default 50% proportion gives the largest, safest sample; entering a better estimate of the true proportion reduces it.
Imibuzo ebuza rhoqo
Ubungakanani besampuli bubalolwa njani?
Ifomula esiseko yi n = z²· p( 1 − p) / e², apho z yixabiso elibalulekileyo lokunyaniseka, p ubungakanani obulindelekileyo ne e umda wemposiso njengenani elipheleleyo. Isiphumo sijikelezwe phezulu kuba awukwazi ukuvavanya umqolo womntu.
Yintoni ukulungisa uqoqosho olugqityiweyo?
Xa uqoqosho lwakho luncinci, ufuna izimvo ezincinci kunefomula esiseko icebisa. Ukulungisa n = n₀ / (1 + (n₀ − 1)/ N) ukhupha umzekelo kubungakanani boqoqosho N. Kubalulekile kakhulu xa umzekelo uyincopho enkulu yento yonke.
Baphi abantu endifunayo ukuba ndifumane inqanaba lokunyaniseka le-95%?
Ixhomekeke kwinqanaba lomonakalo onokuthi uyamkele. Kwi-95% yobuxoki nge-5% yomngcipheko kwaye akukho xabiso elingaphambili, kufuneka uphendule malunga ne-385; umngcipheko we-3% kufuneka uphendule malunga ne-1,068 kunye nomngcipheko we-1% malunga ne-9,604.
Kutheni ubungakanani besampuli bujikelezwe phezulu?
Ungakwazi ukuvavanya inxalenye yomntu, ngoko nasiphi na isiphumo esiphelelwe lixesha sijikelezwe ukuya kwinani elipheleleyo elilandelayo. Ukujikeleza phezulu kunokuba phantsi kuqinisekisile umda wemposiso awunakuba mkhulu kunenjongo yakho.
Ingaba ndimele ndishiye ubungakanani boqoqosho olungagqibekanga?
Leave it at zero (or blank) when the population is very large or unknown, which gives the standard "infinite population" sample size. Enter a real population only when it is small enough that the correction meaningfully reduces the sample.
Ndiyikhuphe njani ubungakanani besampuli efunekayo?
Accept a larger margin of error, use a lower confidence level, or supply a proportion further from 50% if you have a reliable estimate. Each of these lowers the number of responses the formula demands.
API — sebenzisa le calculator ukusuka kwikhowudi
Nceda le khadi lemali njengendawo esemva ye-JSON ekhululekileyo - akukho qhosha lifunekayo. Thumela amaxabiso endawo ezantsi njengeparameter yombuzo okanye i-JSON. Nantoni na oyenzayo isebenzisa okungagqibekanga okufanayo eli phepha ligqityiwe ngaphambili; iparameter engaziwayo yi 400, ayikho i zero ekhululekileyo. Funda i-API epheleleyo →
Incopho yesiphelo
GET https://calculator.free/api/v1/sample-size/curl
curl "https://calculator.free/api/v1/sample-size/?conf=1.96&e=5"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/sample-size/?" + new URLSearchParams({
"conf": "1.96",
"e": "5"
}));
const data = await r.json();
console.log(data.results);Results are estimates for general guidance only, not financial, medical or tax advice.