Discrete Distributions

Cumulative Binomial Distribution Table: P(X ≤ x)

The probability of at most x successes in n independent trials, for n from 1 to 20.

  • n = 1 to 20
  • 15 values of p
  • Calculator included

Cumulative Binomial Table

Jump to a value of n below. Rows: number of successes x · Columns: probability of success p · Cells: P(X ≤ x)

n = 1

n = 1
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.99000.95000.90000.80000.75000.70000.60000.50000.40000.30000.25000.20000.10000.05000.0100
11.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 2

n = 2
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.98010.90250.81000.64000.56250.49000.36000.25000.16000.09000.06250.04000.01000.00250.0001
10.99990.99750.99000.96000.93750.91000.84000.75000.64000.51000.43750.36000.19000.09750.0199
21.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 3

n = 3
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.97030.85740.72900.51200.42190.34300.21600.12500.06400.02700.01560.00800.00100.00010+
10.99970.99280.97200.89600.84380.78400.64800.50000.35200.21600.15620.10400.02800.00730.0003
21−0.99990.99900.99200.98440.97300.93600.87500.78400.65700.57810.48800.27100.14260.0297
31.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 4

n = 4
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.96060.81450.65610.40960.31640.24010.12960.06250.02560.00810.00390.00160.00010+0+
10.99940.98600.94770.81920.73830.65170.47520.31250.17920.08370.05080.02720.00370.00050+
21−0.99950.99630.97280.94920.91630.82080.68750.52480.34830.26170.18080.05230.01400.0006
31−1−0.99990.99840.99610.99190.97440.93750.87040.75990.68360.59040.34390.18550.0394
41.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 5

n = 5
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.95100.77380.59050.32770.23730.16810.07780.03120.01020.00240.00100.00030+0+0+
10.99900.97740.91850.73730.63280.52820.33700.18750.08700.03080.01560.00670.00050+0+
21−0.99880.99140.94210.89650.83690.68260.50000.31740.16310.10350.05790.00860.00120+
31−1−0.99950.99330.98440.96920.91300.81250.66300.47180.36720.26270.08150.02260.0010
41−1−1−0.99970.99900.99760.98980.96880.92220.83190.76270.67230.40950.22620.0490
51.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 6

n = 6
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.94150.73510.53140.26210.17800.11760.04670.01560.00410.00070.00020.00010+0+0+
10.99850.96720.88570.65540.53390.42020.23330.10940.04100.01090.00460.00160.00010+0+
21−0.99780.98410.90110.83060.74430.54430.34380.17920.07050.03760.01700.00130.00010+
31−0.99990.99870.98300.96240.92950.82080.65620.45570.25570.16940.09890.01580.00220+
41−1−0.99990.99840.99540.98910.95900.89060.76670.57980.46610.34460.11430.03280.0015
51−1−1−0.99990.99980.99930.99590.98440.95330.88240.82200.73790.46860.26490.0585
61.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 7

n = 7
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.93210.69830.47830.20970.13350.08240.02800.00780.00160.00020.00010+0+0+0+
10.99800.95560.85030.57670.44490.32940.15860.06250.01880.00380.00130.00040+0+0+
21−0.99620.97430.85200.75640.64710.41990.22660.09630.02880.01290.00470.00020+0+
31−0.99980.99730.96670.92940.87400.71020.50000.28980.12600.07060.03330.00270.00020+
41−1−0.99980.99530.98710.97120.90370.77340.58010.35290.24360.14800.02570.00380+
51−1−1−0.99960.99870.99620.98120.93750.84140.67060.55510.42330.14970.04440.0020
61−1−1−1−0.99990.99980.99840.99220.97200.91760.86650.79030.52170.30170.0679
71.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 8

n = 8
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.92270.66340.43050.16780.10010.05760.01680.00390.00070.00010+0+0+0+0+
10.99730.94280.81310.50330.36710.25530.10640.03520.00850.00130.00040.00010+0+0+
20.99990.99420.96190.79690.67850.55180.31540.14450.04980.01130.00420.00120+0+0+
31−0.99960.99500.94370.88620.80590.59410.36330.17370.05800.02730.01040.00040+0+
41−1−0.99960.98960.97270.94200.82630.63670.40590.19410.11380.05630.00500.00040+
51−1−1−0.99880.99580.98870.95020.85550.68460.44820.32150.20310.03810.00580.0001
61−1−1−0.99990.99960.99870.99150.96480.89360.74470.63290.49670.18690.05720.0027
71−1−1−1−1−0.99990.99930.99610.98320.94240.89990.83220.56950.33660.0773
81.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 9

n = 9
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.91350.63020.38740.13420.07510.04040.01010.00200.00030+0+0+0+0+0+
10.99660.92880.77480.43620.30030.19600.07050.01950.00380.00040.00010+0+0+0+
20.99990.99160.94700.73820.60070.46280.23180.08980.02500.00430.00130.00030+0+0+
31−0.99940.99170.91440.83430.72970.48260.25390.09940.02530.01000.00310.00010+0+
41−1−0.99910.98040.95110.90120.73340.50000.26660.09880.04890.01960.00090+0+
51−1−0.99990.99690.99000.97470.90060.74610.51740.27030.16570.08560.00830.00060+
61−1−1−0.99970.99870.99570.97500.91020.76820.53720.39930.26180.05300.00840.0001
71−1−1−1−0.99990.99960.99620.98050.92950.80400.69970.56380.22520.07120.0034
81.00001−1−1−1−1−0.99970.99800.98990.95960.92490.86580.61260.36980.0865
91.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 10

n = 10
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.90440.59870.34870.10740.05630.02820.00600.00100.00010+0+0+0+0+0+
10.99570.91390.73610.37580.24400.14930.04640.01070.00170.00010+0+0+0+0+
20.99990.98850.92980.67780.52560.38280.16730.05470.01230.00160.00040.00010+0+0+
31−0.99900.98720.87910.77590.64960.38230.17190.05480.01060.00350.00090+0+0+
41−0.99990.99840.96720.92190.84970.63310.37700.16620.04730.01970.00640.00010+0+
51−1−0.99990.99360.98030.95270.83380.62300.36690.15030.07810.03280.00160.00010+
61−1−1−0.99910.99650.98940.94520.82810.61770.35040.22410.12090.01280.00100+
71−1−1−0.99990.99960.99840.98770.94530.83270.61720.47440.32220.07020.01150.0001
81.00001−1−1−1−0.99990.99830.98930.95360.85070.75600.62420.26390.08610.0043
91.00001−1−1−1−1−0.99990.99900.99400.97180.94370.89260.65130.40130.0956
101.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 11

n = 11
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.89530.56880.31380.08590.04220.01980.00360.00050+0+0+0+0+0+0+
10.99480.89810.69740.32210.19710.11300.03020.00590.00070+0+0+0+0+0+
20.99980.98480.91040.61740.45520.31270.11890.03270.00590.00060.00010+0+0+0+
31−0.99840.98150.83890.71330.56960.29630.11330.02930.00430.00120.00020+0+0+
41−0.99990.99720.94960.88540.78970.53280.27440.09940.02160.00760.00200+0+0+
51−1−0.99970.98830.96570.92180.75350.50000.24650.07820.03430.01170.00030+0+
61−1−1−0.99800.99240.97840.90060.72560.46720.21030.11460.05040.00280.00010+
71−1−1−0.99980.99880.99570.97070.88670.70370.43040.28670.16110.01850.00160+
81.00001−1−1−0.99990.99940.99410.96730.88110.68730.54480.38260.08960.01520.0002
91.00001−1−1−1−1−0.99930.99410.96980.88700.80290.67790.30260.10190.0052
101.00001−1−1−1−1−1−0.99950.99640.98020.95780.91410.68620.43120.1047
111.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 12

n = 12
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.88640.54040.28240.06870.03170.01380.00220.00020+0+0+0+0+0+0+
10.99380.88160.65900.27490.15840.08500.01960.00320.00030+0+0+0+0+0+
20.99980.98040.88910.55830.39070.25280.08340.01930.00280.00020+0+0+0+0+
31−0.99780.97440.79460.64880.49250.22530.07300.01530.00170.00040.00010+0+0+
41−0.99980.99570.92740.84240.72370.43820.19380.05730.00950.00280.00060+0+0+
51−1−0.99950.98060.94560.88220.66520.38720.15820.03860.01430.00390.00010+0+
61−1−0.99990.99610.98570.96140.84180.61280.33480.11780.05440.01940.00050+0+
71−1−1−0.99940.99720.99050.94270.80620.56180.27630.15760.07260.00430.00020+
81−1−1−0.99990.99960.99830.98470.92700.77470.50750.35120.20540.02560.00220+
91.00001−1−1−1−0.99980.99720.98070.91660.74720.60930.44170.11090.01960.0002
101.00001−1−1−1−1−0.99970.99680.98040.91500.84160.72510.34100.11840.0062
111.00001−1−1−1−1−1−0.99980.99780.98620.96830.93130.71760.45960.1136
121.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 13

n = 13
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.87750.51330.25420.05500.02380.00970.00130.00010+0+0+0+0+0+0+
10.99280.86460.62130.23360.12670.06370.01260.00170.00010+0+0+0+0+0+
20.99970.97550.86610.50170.33260.20250.05790.01120.00130.00010+0+0+0+0+
31−0.99690.96580.74730.58430.42060.16860.04610.00780.00070.00010+0+0+0+
41−0.99970.99350.90090.79400.65430.35300.13340.03210.00400.00100.00020+0+0+
51−1−0.99910.97000.91980.83460.57440.29050.09770.01820.00560.00120+0+0+
61−1−0.99990.99300.97570.93760.77120.50000.22880.06240.02430.00700.00010+0+
71−1−1−0.99880.99440.98180.90230.70950.42560.16540.08020.03000.00090+0+
81−1−1−0.99980.99900.99600.96790.86660.64700.34570.20600.09910.00650.00030+
91.00001−1−1−0.99990.99930.99220.95390.83140.57940.41570.25270.03420.00310+
101.00001−1−1−1−0.99990.99870.98880.94210.79750.66740.49830.13390.02450.0003
111.00001−1−1−1−1−0.99990.99830.98740.93630.87330.76640.37870.13540.0072
121.00001.00001−1−1−1−1−0.99990.99870.99030.97620.94500.74580.48670.1225
131.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 14

n = 14
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.86870.48770.22880.04400.01780.00680.00080.00010+0+0+0+0+0+0+
10.99160.84700.58460.19790.10100.04750.00810.00090.00010+0+0+0+0+0+
20.99970.96990.84160.44810.28110.16080.03980.00650.00060+0+0+0+0+0+
31−0.99580.95590.69820.52130.35520.12430.02870.00390.00020+0+0+0+0+
41−0.99960.99080.87020.74150.58420.27930.08980.01750.00170.00030+0+0+0+
51−1−0.99850.95610.88830.78050.48590.21200.05830.00830.00220.00040+0+0+
61−1−0.99980.98840.96170.90670.69250.39530.15010.03150.01030.00240+0+0+
71−1−1−0.99760.98970.96850.84990.60470.30750.09330.03830.01160.00020+0+
81−1−1−0.99960.99780.99170.94170.78800.51410.21950.11170.04390.00150+0+
91.00001−1−1−0.99970.99830.98250.91020.72070.41580.25850.12980.00920.00040+
101.00001−1−1−1−0.99980.99610.97130.87570.64480.47870.30180.04410.00420+
111.00001−1−1−1−1−0.99940.99350.96020.83920.71890.55190.15840.03010.0003
121.00001−1−1−1−1−0.99990.99910.99190.95250.89900.80210.41540.15300.0084
131.00001.00001−1−1−1−1−0.99990.99920.99320.98220.95600.77120.51230.1313
141.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 15

n = 15
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.86010.46330.20590.03520.01340.00470.00050+0+0+0+0+0+0+0+
10.99040.82900.54900.16710.08020.03530.00520.00050+0+0+0+0+0+0+
20.99960.96380.81590.39800.23610.12680.02710.00370.00030+0+0+0+0+0+
31−0.99450.94440.64820.46130.29690.09050.01760.00190.00010+0+0+0+0+
41−0.99940.98730.83580.68650.51550.21730.05920.00930.00070.00010+0+0+0+
51−0.99990.99780.93890.85160.72160.40320.15090.03380.00370.00080.00010+0+0+
61−1−0.99970.98190.94340.86890.60980.30360.09500.01520.00420.00080+0+0+
71−1−1−0.99580.98270.95000.78690.50000.21310.05000.01730.00420+0+0+
81−1−1−0.99920.99580.98480.90500.69640.39020.13110.05660.01810.00030+0+
91.00001−1−0.99990.99920.99630.96620.84910.59680.27840.14840.06110.00220.00010+
101.00001−1−1−0.99990.99930.99070.94080.78270.48450.31350.16420.01270.00060+
111.00001−1−1−1−0.99990.99810.98240.90950.70310.53870.35180.05560.00550+
121.00001−1−1−1−1−0.99970.99630.97290.87320.76390.60200.18410.03620.0004
131.00001.00001−1−1−1−1−0.99950.99480.96470.91980.83290.45100.17100.0096
141.00001.00001−1−1−1−1−1−0.99950.99530.98660.96480.79410.53670.1399
151.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 16

n = 16
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.85150.44010.18530.02810.01000.00330.00030+0+0+0+0+0+0+0+
10.98910.81080.51470.14070.06350.02610.00330.00030+0+0+0+0+0+0+
20.99950.95710.78920.35180.19710.09940.01830.00210.00010+0+0+0+0+0+
31−0.99300.93160.59810.40500.24590.06510.01060.00090+0+0+0+0+0+
41−0.99910.98300.79820.63020.44990.16660.03840.00490.00030+0+0+0+0+
51−0.99990.99670.91830.81030.65980.32880.10510.01910.00160.00030+0+0+0+
61−1−0.99950.97330.92040.82470.52720.22720.05830.00710.00160.00020+0+0+
71−1−0.99990.99300.97290.92560.71610.40180.14230.02570.00750.00150+0+0+
81−1−1−0.99850.99250.97430.85770.59820.28390.07440.02710.00700.00010+0+
91−1−1−0.99980.99840.99290.94170.77280.47280.17530.07960.02670.00050+0+
101.00001−1−1−0.99970.99840.98090.89490.67120.34020.18970.08170.00330.00010+
111.00001−1−1−1−0.99970.99510.96160.83340.55010.36980.20180.01700.00090+
121.00001−1−1−1−1−0.99910.98940.93490.75410.59500.40190.06840.00700+
131.00001−1−1−1−1−0.99990.99790.98170.90060.80290.64820.21080.04290.0005
141.00001.00001−1−1−1−1−0.99970.99670.97390.93650.85930.48530.18920.0109
151.00001.00001−1−1−1−1−1−0.99970.99670.99000.97190.81470.55990.1485
161.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 17

n = 17
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.84290.41810.16680.02250.00750.00230.00020+0+0+0+0+0+0+0+
10.98770.79220.48180.11820.05010.01930.00210.00010+0+0+0+0+0+0+
20.99940.94970.76180.30960.16370.07740.01230.00120.00010+0+0+0+0+0+
31−0.99120.91740.54890.35300.20190.04640.00640.00050+0+0+0+0+0+
41−0.99880.97790.75820.57390.38870.12600.02450.00250.00010+0+0+0+0+
51−0.99990.99530.89430.76530.59680.26390.07170.01060.00070.00010+0+0+0+
61−1−0.99920.96230.89290.77520.44780.16620.03480.00320.00060.00010+0+0+
71−1−0.99990.98910.95980.89540.64050.31450.09190.01270.00310.00050+0+0+
81−1−1−0.99740.98760.95970.80110.50000.19890.04030.01240.00260+0+0+
91−1−1−0.99950.99690.98730.90810.68550.35950.10460.04020.01090.00010+0+
101.00001−1−0.99990.99940.99680.96520.83380.55220.22480.10710.03770.00080+0+
111.00001−1−1−0.99990.99930.98940.92830.73610.40320.23470.10570.00470.00010+
121.00001−1−1−1−0.99990.99750.97550.87400.61130.42610.24180.02210.00120+
131.00001−1−1−1−1−0.99950.99360.95360.79810.64700.45110.08260.00880+
141.00001.00001−1−1−1−0.99990.99880.98770.92260.83630.69040.23820.05030.0006
151.00001.00001−1−1−1−1−0.99990.99790.98070.94990.88180.51820.20780.0123
161.00001.00001.00001−1−1−1−1−0.99980.99770.99250.97750.83320.58190.1571
171.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 18

n = 18
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.83450.39720.15010.01800.00560.00160.00010+0+0+0+0+0+0+0+
10.98620.77350.45030.09910.03950.01420.00130.00010+0+0+0+0+0+0+
20.99930.94190.73380.27130.13530.06000.00820.00070+0+0+0+0+0+0+
31−0.98910.90180.50100.30570.16460.03280.00380.00020+0+0+0+0+0+
41−0.99850.97180.71640.51870.33270.09420.01540.00130+0+0+0+0+0+
51−0.99980.99360.86710.71750.53440.20880.04810.00580.00030+0+0+0+0+
61−1−0.99880.94870.86100.72170.37430.11890.02030.00140.00020+0+0+0+
71−1−0.99980.98370.94310.85930.56340.24030.05760.00610.00120.00020+0+0+
81−1−1−0.99570.98070.94040.73680.40730.13470.02100.00540.00090+0+0+
91−1−1−0.99910.99460.97900.86530.59270.26320.05960.01930.00430+0+0+
101.00001−1−0.99980.99880.99390.94240.75970.43660.14070.05690.01630.00020+0+
111.00001−1−1−0.99980.99860.97970.88110.62570.27830.13900.05130.00120+0+
121.00001−1−1−1−0.99970.99420.95190.79120.46560.28250.13290.00640.00020+
131.00001−1−1−1−1−0.99870.98460.90580.66730.48130.28360.02820.00150+
141.00001.00001−1−1−1−0.99980.99620.96720.83540.69430.49900.09820.01090+
151.00001.00001−1−1−1−1−0.99930.99180.94000.86470.72870.26620.05810.0007
161.00001.00001−1−1−1−1−0.99990.99870.98580.96050.90090.54970.22650.0138
171.00001.00001.00001−1−1−1−1−0.99990.99840.99440.98200.84990.60280.1655
181.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 19

n = 19
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.82620.37740.13510.01440.00420.00110.00010+0+0+0+0+0+0+0+
10.98470.75470.42030.08290.03100.01040.00080+0+0+0+0+0+0+0+
20.99910.93350.70540.23690.11130.04620.00550.00040+0+0+0+0+0+0+
31−0.98680.88500.45510.26310.13320.02300.00220.00010+0+0+0+0+0+
41−0.99800.96480.67330.46540.28220.06960.00960.00060+0+0+0+0+0+
51−0.99980.99140.83690.66780.47390.16290.03180.00310.00010+0+0+0+0+
61−1−0.99830.93240.82510.66550.30810.08350.01160.00060.00010+0+0+0+
71−1−0.99970.97670.92250.81800.48780.17960.03520.00280.00050+0+0+0+
81−1−1−0.99330.97130.91610.66750.32380.08850.01050.00230.00030+0+0+
91−1−1−0.99840.99110.96740.81390.50000.18610.03260.00890.00160+0+0+
101.00001−1−0.99970.99770.98950.91150.67620.33250.08390.02870.00670+0+0+
111.00001−1−1−0.99950.99720.96480.82040.51220.18200.07750.02330.00030+0+
121.00001−1−1−0.99990.99940.98840.91650.69190.33450.17490.06760.00170+0+
131.00001−1−1−1−0.99990.99690.96820.83710.52610.33220.16310.00860.00020+
141.00001−1−1−1−1−0.99940.99040.93040.71780.53460.32670.03520.00200+
151.00001.00001−1−1−1−0.99990.99780.97700.86680.73690.54490.11500.01320+
161.00001.00001−1−1−1−1−0.99960.99450.95380.88870.76310.29460.06650.0009
171.00001.00001.00001−1−1−1−1−0.99920.98960.96900.91710.57970.24530.0153
181.00001.00001.00001−1−1−1−1−0.99990.99890.99580.98560.86490.62260.1738
191.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

n = 20

n = 20
Probability of success (p) →
x ↓
.01.05.10.20.25.30.40.50.60.70.75.80.90.95.99
00.81790.35850.12160.01150.00320.00080+0+0+0+0+0+0+0+0+
10.98310.73580.39170.06920.02430.00760.00050+0+0+0+0+0+0+0+
20.99900.92450.67690.20610.09130.03550.00360.00020+0+0+0+0+0+0+
31−0.98410.86700.41140.22520.10710.01600.00130+0+0+0+0+0+0+
41−0.99740.95680.62960.41480.23750.05100.00590.00030+0+0+0+0+0+
51−0.99970.98870.80420.61720.41640.12560.02070.00160+0+0+0+0+0+
61−1−0.99760.91330.78580.60800.25000.05770.00650.00030+0+0+0+0+
71−1−0.99960.96790.89820.77230.41590.13160.02100.00130.00020+0+0+0+
81−1−0.99990.99000.95910.88670.59560.25170.05650.00510.00090.00010+0+0+
91−1−1−0.99740.98610.95200.75530.41190.12750.01710.00390.00060+0+0+
101.00001−1−0.99940.99610.98290.87250.58810.24470.04800.01390.00260+0+0+
111.00001−1−0.99990.99910.99490.94350.74830.40440.11330.04090.01000.00010+0+
121.00001−1−1−0.99980.99870.97900.86840.58410.22770.10180.03210.00040+0+
131.00001−1−1−1−0.99970.99350.94230.75000.39200.21420.08670.00240+0+
141.00001−1−1−1−1−0.99840.97930.87440.58360.38280.19580.01130.00030+
151.00001.00001−1−1−1−0.99970.99410.94900.76250.58520.37040.04320.00260+
161.00001.00001−1−1−1−1−0.99870.98400.89290.77480.58860.13300.01590+
171.00001.00001−1−1−1−1−0.99980.99640.96450.90870.79390.32310.07550.0010
181.00001.00001.00001−1−1−1−1−0.99950.99240.97570.93080.60830.26420.0169
191.00001.00001.00001−1−1−1−1−1−0.99920.99680.98850.87840.64150.1821
201.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.00001.0000

Tip: click any value to highlight its row and column.

How to read this table

  1. Find the block for your number of trials n.
  2. Go to the row for x and the column for p.
  3. The cell is P(X ≤ x). For P(X ≥ x) use 1 − P(X ≤ x − 1); for P(a ≤ X ≤ b) use P(X ≤ b) − P(X ≤ a − 1).
  4. 0+ means a probability that is positive but below 0.00005; 1− means one that is below 1 but above 0.99995.

Worked example

In a Phase II trial of 10 patients with a true response rate of 20%, the chance of at most 2 responses is row x = 2, column p = .20 in the n = 10 block: 0.6778. The chance of 3 or more responses is 1 − 0.6778 = 0.3222.

This is the calculation behind single-arm Phase II designs such as Simon's two-stage design, which choose sample sizes and response thresholds from binomial probabilities.

Click the underlined links to highlight the value in the table.

Calculator

For values between the rows and columns of the table. Results update as you type.

Formula and how the values were computed

P(X = x) = C(n, x) px (1 − p)n − x ·  P(X ≤ x) = Σk=0x P(X = k)

Each cell is computed exactly from the binomial formula and rounded to four decimals.

Frequently asked questions

What are the conditions for a binomial distribution?

A fixed number of trials n, two outcomes per trial, the same probability of success p on every trial, and independent trials.

What if n is larger than 20?

Use the calculator above, which handles any n. When np and n(1 − p) are both at least about 10, the normal approximation with mean np and variance np(1 − p) also works well.

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