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Qualifying for character classes in Advanced Dungeons & Dragons Part 2: Multiple Attempts

In the previous article we looked at how to find the probability of qualifying for the various AD&D character classes. Here we expand on that to find the probabilities of qualifying in multiple attempts.

Given a probability $p$ of qualifying in a single attempt, the probability of qualifying exactly $r$ times in $n$ attempts has a binomial distribution: $$\frac{n!}{r!(n-r)!}\;p^r(1-p)^{n-r}.$$

The probability of qualifying at least once in $n$ attempts is therefore $$\sum_{r=1}^n\frac{n!}{r!(n-r)!}\;p^r(1-p)^{n-r}.$$

Alternatively, since the probability of failing to qualify in $n$ attempts is $(1-p)^n$, it follows that the probability of qualifying at least once is $1-(1-p)^n$.

The following table shows the results for each type of character for 1 to 8 attempts.

UnorderedOrdered
CharacterAttempts3d63/4d63d63/4d6

Cleric197.140%99.805%61.280%85.434%
299.918%100.000%85.008%97.878%
399.998%100.000%94.195%99.691%
4100.000%100.000%97.752%99.955%
5100.000%100.000%99.130%99.993%
6100.000%100.000%99.663%99.999%
7100.000%100.000%99.870%100.000%
8100.000%100.000%99.949%100.000%

Druid130.868%73.455%2.873%13.622%
252.208%92.954%5.663%25.388%
366.961%98.130%8.372%35.552%
477.159%99.504%11.004%44.331%
584.210%99.868%13.561%51.914%
689.084%99.965%16.044%58.464%
792.454%99.991%18.455%64.122%
894.783%99.998%20.798%69.009%

Fighter197.140%99.805%58.305%84.033%
299.918%100.000%82.616%97.451%
399.998%100.000%92.752%99.593%
4100.000%100.000%96.978%99.935%
5100.000%100.000%98.740%99.990%
6100.000%100.000%99.475%99.998%
7100.000%100.000%99.781%100.000%
8100.000%100.000%99.909%100.000%

Paladin13.966%24.171%0.094%1.378%
27.774%42.500%0.188%2.736%
311.432%56.398%0.282%4.076%
414.944%66.937%0.376%5.398%
518.317%74.929%0.470%6.701%
621.556%80.989%0.564%7.987%
724.667%85.584%0.658%9.254%
827.655%89.069%0.751%10.505%

Ranger13.256%29.351%0.161%2.927%
26.407%50.088%0.321%5.768%
39.454%64.738%0.481%8.526%
412.403%75.088%0.641%11.204%
515.255%82.400%0.800%13.803%
618.015%87.566%0.959%16.326%
720.685%91.215%1.118%18.775%
823.268%93.794%1.277%21.152%

Magic-user197.140%99.805%61.280%85.434%
299.918%100.000%85.008%97.878%
399.998%100.000%94.195%99.691%
4100.000%100.000%97.752%99.955%
5100.000%100.000%99.130%99.993%
6100.000%100.000%99.663%99.999%
7100.000%100.000%99.870%100.000%
8100.000%100.000%99.949%100.000%

Illusionist17.562%35.744%0.372%2.915%
214.553%58.712%0.742%5.745%
321.015%73.470%1.111%8.492%
426.988%82.953%1.479%11.160%
532.509%89.046%1.845%13.749%
637.613%92.962%2.210%16.264%
742.331%95.477%2.574%18.704%
846.692%97.094%2.936%21.074%

Thief197.140%99.805%61.280%85.434%
299.918%100.000%85.008%97.878%
399.998%100.000%94.195%99.691%
4100.000%100.000%97.752%99.955%
5100.000%100.000%99.130%99.993%
6100.000%100.000%99.663%99.999%
7100.000%100.000%99.870%100.000%
8100.000%100.000%99.949%100.000%

Assassin158.571%93.483%6.395%27.134%
282.837%99.575%12.382%46.906%
392.889%99.972%17.985%61.312%
497.054%99.998%23.230%71.810%
598.780%100.000%28.140%79.459%
699.494%100.000%32.735%85.033%
799.791%100.000%37.037%89.094%
899.913%100.000%41.064%92.053%

Monk17.625%39.576%0.372%3.781%
214.669%63.489%0.742%7.419%
321.176%77.938%1.111%10.920%
427.186%86.669%1.479%14.288%
532.738%91.945%1.845%17.529%
637.867%95.133%2.210%20.647%
742.605%97.059%2.574%23.647%
846.981%98.223%2.936%26.534%

Bard10.027%1.581%0.002%0.146%
20.053%3.138%0.003%0.292%
30.080%4.670%0.005%0.437%
40.106%6.177%0.007%0.583%
50.133%7.661%0.009%0.728%
60.159%9.121%0.010%0.873%
70.186%10.558%0.012%1.018%
80.213%11.973%0.014%1.162%

Half-elf Cleric175.236%93.253%58.443%84.445%
293.868%99.545%82.730%97.580%
398.481%99.969%92.823%99.624%
499.624%99.998%97.018%99.941%
599.907%100.000%98.761%99.991%
699.977%100.000%99.485%99.999%
799.994%100.000%99.786%100.000%
899.999%100.000%99.911%100.000%

Half-orc Cleric192.909%99.643%21.788%51.230%
299.497%99.999%38.829%76.215%
399.964%100.000%52.157%88.400%
499.997%100.000%62.581%94.343%
5100.000%100.000%70.734%97.241%
6100.000%100.000%77.110%98.654%
7100.000%100.000%82.098%99.344%
8100.000%100.000%85.998%99.680%

Half-elf Druid130.868%73.455%2.873%13.622%
252.208%92.954%5.663%25.388%
366.961%98.130%8.372%35.552%
477.159%99.504%11.004%44.331%
584.210%99.868%13.561%51.914%
689.084%99.965%16.044%58.464%
792.454%99.991%18.455%64.122%
894.783%99.998%20.798%69.009%

Dwarf Fighter195.464%99.763%30.568%62.123%
299.794%99.999%51.792%85.653%
399.991%100.000%66.528%94.566%
4100.000%100.000%76.760%97.942%
5100.000%100.000%83.864%99.220%
6100.000%100.000%88.796%99.705%
7100.000%100.000%92.221%99.888%
8100.000%100.000%94.599%99.958%

Elf Fighter173.219%93.089%39.643%73.306%
292.828%99.522%63.570%92.874%
398.079%99.967%78.012%98.098%
499.486%99.998%86.729%99.492%
599.862%100.000%91.990%99.864%
699.963%100.000%95.165%99.964%
799.990%100.000%97.082%99.990%
899.997%100.000%98.239%99.997%

Gnome Fighter175.222%93.253%48.858%79.235%
293.861%99.545%73.845%95.688%
398.479%99.969%86.624%99.105%
499.623%99.998%93.159%99.814%
599.907%100.000%96.501%99.961%
699.977%100.000%98.211%99.992%
799.994%100.000%99.085%99.998%
899.999%100.000%99.532%100.000%

Half-elf Fighter194.949%99.368%58.035%83.968%
299.745%99.996%82.390%97.430%
399.987%100.000%92.610%99.588%
499.999%100.000%96.899%99.934%
5100.000%100.000%98.699%99.989%
6100.000%100.000%99.454%99.998%
7100.000%100.000%99.771%100.000%
8100.000%100.000%99.904%100.000%

Halfling Fighter173.678%93.193%30.747%63.877%
293.071%99.537%52.040%86.951%
398.176%99.968%66.786%95.286%
499.520%99.998%76.999%98.297%
599.874%100.000%84.071%99.385%
699.967%100.000%88.969%99.778%
799.991%100.000%92.360%99.920%
899.998%100.000%94.709%99.971%

Half-orc Fighter191.247%99.481%23.950%53.550%
299.234%99.997%42.164%78.424%
399.933%100.000%56.016%89.978%
499.994%100.000%66.550%95.345%
599.999%100.000%74.561%97.838%
6100.000%100.000%80.654%98.996%
7100.000%100.000%85.287%99.533%
8100.000%100.000%88.811%99.783%

Half-elf Ranger13.256%29.351%0.161%2.927%
26.407%50.088%0.321%5.768%
39.454%64.738%0.481%8.526%
412.403%75.088%0.641%11.204%
515.255%82.400%0.800%13.803%
618.015%87.566%0.959%16.326%
720.685%91.215%1.118%18.775%
823.268%93.794%1.277%21.152%

Elf Magic-user197.089%99.804%51.230%80.163%
299.915%100.000%76.214%96.065%
399.998%100.000%88.400%99.219%
4100.000%100.000%94.342%99.845%
5100.000%100.000%97.241%99.969%
6100.000%100.000%98.654%99.994%
7100.000%100.000%99.344%99.999%
8100.000%100.000%99.680%100.000%

Half-elf Magic-user197.140%99.805%61.280%85.434%
299.918%100.000%85.008%97.878%
399.998%100.000%94.195%99.691%
4100.000%100.000%97.752%99.955%
5100.000%100.000%99.130%99.993%
6100.000%100.000%99.663%99.999%
7100.000%100.000%99.870%100.000%
8100.000%100.000%99.949%100.000%

Gnome Illusionist16.269%33.908%0.312%2.749%
212.144%56.319%0.622%5.421%
317.652%71.130%0.932%8.021%
422.814%80.920%1.241%10.549%
527.652%87.389%1.548%13.008%
632.188%91.665%1.855%15.399%
736.439%94.492%2.161%17.724%
840.423%96.359%2.466%19.985%

Dwarf Thief194.713%99.731%26.858%59.262%
299.720%99.999%46.503%83.404%
399.985%100.000%60.871%93.239%
499.999%100.000%71.380%97.246%
5100.000%100.000%79.067%98.878%
6100.000%100.000%84.689%99.543%
7100.000%100.000%88.802%99.814%
8100.000%100.000%91.809%99.924%

Elf Thief196.171%99.771%50.920%80.558%
299.853%99.999%75.912%96.220%
399.994%100.000%88.178%99.265%
4100.000%100.000%94.198%99.857%
5100.000%100.000%97.152%99.972%
6100.000%100.000%98.602%99.995%
7100.000%100.000%99.314%99.999%
8100.000%100.000%99.663%100.000%

Gnome Thief197.089%99.804%51.230%80.163%
299.915%100.000%76.214%96.065%
399.998%100.000%88.400%99.219%
4100.000%100.000%94.342%99.845%
5100.000%100.000%97.241%99.969%
6100.000%100.000%98.654%99.994%
7100.000%100.000%99.344%99.999%
8100.000%100.000%99.680%100.000%

Half-elf Thief197.140%99.805%61.280%85.434%
299.918%100.000%85.008%97.878%
399.998%100.000%94.195%99.691%
4100.000%100.000%97.752%99.955%
5100.000%100.000%99.130%99.993%
6100.000%100.000%99.663%99.999%
7100.000%100.000%99.870%100.000%
8100.000%100.000%99.949%100.000%

Halfling Thief196.883%99.802%43.225%73.874%
299.903%100.000%67.766%93.174%
399.997%100.000%81.699%98.217%
4100.000%100.000%89.610%99.534%
5100.000%100.000%94.101%99.878%
6100.000%100.000%96.651%99.968%
7100.000%100.000%98.098%99.992%
8100.000%100.000%98.920%99.998%

Half-orc Thief192.909%99.643%21.788%51.230%
299.497%99.999%38.829%76.215%
399.964%100.000%52.157%88.400%
499.997%100.000%62.581%94.343%
5100.000%100.000%70.734%97.241%
6100.000%100.000%77.110%98.654%
7100.000%100.000%82.098%99.344%
8100.000%100.000%85.998%99.680%

Dwarf Assassin132.381%79.058%3.337%20.044%
254.277%95.614%6.563%36.070%
369.082%99.081%9.682%48.884%
479.094%99.808%12.696%59.130%
585.864%99.960%15.609%67.322%
690.441%99.992%18.426%73.872%
793.536%99.998%21.148%79.109%
895.629%100.000%23.780%83.296%

Elf Assassin151.151%88.806%6.798%29.827%
276.137%98.747%13.135%50.757%
388.343%99.860%19.040%65.445%
494.306%99.984%24.544%75.752%
597.218%99.998%29.674%82.984%
698.641%100.000%34.455%88.059%
799.336%100.000%38.911%91.621%
899.676%100.000%43.064%94.120%

Gnome Assassin157.852%93.361%5.619%25.884%
282.235%99.559%10.923%45.069%
392.512%99.971%15.928%59.287%
496.844%99.998%20.652%69.826%
598.670%100.000%25.111%77.636%
699.439%100.000%29.319%83.425%
799.764%100.000%33.291%87.715%
899.900%100.000%37.039%90.895%

Half-elf Assassin158.571%93.483%6.395%27.134%
282.837%99.575%12.382%46.906%
392.889%99.972%17.985%61.312%
497.054%99.998%23.230%71.810%
598.780%100.000%28.140%79.459%
699.494%100.000%32.735%85.033%
799.791%100.000%37.037%89.094%
899.913%100.000%41.064%92.053%

Half-orc Assassin131.003%78.002%3.291%19.982%
252.394%95.161%6.473%35.971%
367.154%98.935%9.551%48.765%
477.337%99.766%12.527%59.003%
584.363%99.948%15.406%67.195%
689.211%99.989%18.190%73.750%
792.556%99.998%20.882%78.995%
894.864%99.999%23.486%83.193%

Half-elf Bard10.027%1.581%0.002%0.146%
20.053%3.138%0.003%0.292%
30.080%4.670%0.005%0.437%
40.106%6.177%0.007%0.583%
50.133%7.661%0.009%0.728%
60.159%9.121%0.010%0.873%
70.186%10.558%0.012%1.018%
80.213%11.973%0.014%1.162%

Half-elf Cleric/Fighter175.038%93.249%43.189%75.215%
293.769%99.544%67.725%93.857%
398.445%99.969%81.665%98.477%
499.612%99.998%89.583%99.623%
599.903%100.000%94.082%99.906%
699.976%100.000%96.638%99.977%
799.994%100.000%98.090%99.994%
899.998%100.000%98.915%99.999%

Half-orc Cleric/Fighter169.795%92.831%17.741%47.931%
290.877%99.486%32.334%72.888%
397.244%99.963%44.339%85.883%
499.168%99.997%54.214%92.649%
599.749%100.000%62.336%96.173%
699.924%100.000%69.018%98.007%
799.977%100.000%74.515%98.962%
899.993%100.000%79.036%99.460%

Half-elf Cleric/Fighter/Magic-user173.268%93.152%33.545%68.110%
292.854%99.531%55.837%89.830%
398.090%99.968%70.652%96.757%
499.489%99.998%80.497%98.966%
599.863%100.000%87.039%99.670%
699.964%100.000%91.387%99.895%
799.990%100.000%94.276%99.966%
899.997%100.000%96.196%99.989%

Half-elf Cleric/Ranger13.256%29.351%0.161%2.927%
26.407%50.088%0.321%5.768%
39.454%64.738%0.481%8.526%
412.403%75.088%0.641%11.204%
515.255%82.400%0.800%13.803%
618.015%87.566%0.959%16.326%
720.685%91.215%1.118%18.775%
823.268%93.794%1.277%21.152%

Half-elf Cleric/Magic-user175.042%93.250%45.393%76.468%
293.771%99.544%70.180%94.463%
398.445%99.969%83.716%98.697%
499.612%99.998%91.108%99.693%
599.903%100.000%95.144%99.928%
699.976%100.000%97.348%99.983%
799.994%100.000%98.552%99.996%
899.998%100.000%99.209%99.999%

Half-orc Cleric/Thief179.540%97.012%16.139%45.854%
295.814%99.911%29.674%70.682%
399.143%99.997%41.024%84.126%
499.825%100.000%50.542%91.405%
599.964%100.000%58.524%95.346%
699.993%100.000%65.218%97.480%
799.998%100.000%70.832%98.636%
8100.000%100.000%75.539%99.261%

Half-orc Cleric/Assassin117.116%59.696%2.182%17.127%
231.303%83.756%4.317%31.321%
343.061%93.453%6.405%43.084%
452.807%97.361%8.447%52.833%
560.884%98.937%10.445%60.911%
667.580%99.571%12.399%67.606%
773.129%99.827%14.311%73.154%
877.728%99.930%16.181%77.752%

Elf Fighter/Magic-user173.137%93.087%35.044%69.587%
292.784%99.522%57.807%90.750%
398.062%99.967%72.593%97.187%
499.479%99.998%82.197%99.144%
599.860%100.000%88.436%99.740%
699.962%100.000%92.488%99.921%
799.990%100.000%95.121%99.976%
899.997%100.000%96.831%99.993%

Half-elf Fighter/Magic-user175.038%93.249%43.189%75.215%
293.769%99.544%67.725%93.857%
398.445%99.969%81.665%98.477%
499.612%99.998%89.583%99.623%
599.903%100.000%94.082%99.906%
699.976%100.000%96.638%99.977%
799.994%100.000%98.090%99.994%
899.998%100.000%98.915%99.999%

Gnome Fighter/Illusionist16.210%33.885%0.242%2.489%
212.034%56.288%0.483%4.916%
317.496%71.100%0.724%7.282%
422.619%80.893%0.965%9.590%
527.424%87.367%1.204%11.840%
631.931%91.648%1.443%14.034%
736.158%94.478%1.682%16.174%
840.122%96.349%1.920%18.260%

Dwarf Fighter/Thief172.650%93.127%22.643%55.604%
292.520%99.528%40.159%80.290%
397.954%99.968%53.709%91.249%
499.440%99.998%64.190%96.115%
599.847%100.000%72.299%98.275%
699.958%100.000%78.571%99.234%
799.989%100.000%83.423%99.660%
899.997%100.000%87.177%99.849%

Elf Fighter/Thief163.313%90.632%34.832%69.930%
286.541%99.122%57.531%90.958%
395.062%99.918%72.324%97.281%
498.188%99.992%81.964%99.182%
599.335%99.999%88.246%99.754%
699.756%100.000%92.340%99.926%
799.911%100.000%95.008%99.978%
899.967%100.000%96.747%99.993%

Gnome Fighter/Thief174.781%93.237%37.948%71.751%
293.640%99.543%61.495%92.020%
398.396%99.969%76.107%97.746%
499.596%99.998%85.174%99.363%
599.898%100.000%90.800%99.820%
699.974%100.000%94.291%99.949%
799.994%100.000%96.458%99.986%
899.998%100.000%97.802%99.996%

Half-elf Fighter/Thief175.038%93.249%43.189%75.215%
293.769%99.544%67.725%93.857%
398.445%99.969%81.665%98.477%
499.612%99.998%89.583%99.623%
599.903%100.000%94.082%99.906%
699.976%100.000%96.638%99.977%
799.994%100.000%98.090%99.994%
899.998%100.000%98.915%99.999%

Halfling Fighter/Thief173.575%93.189%28.394%61.950%
293.017%99.536%48.726%85.522%
398.155%99.968%63.284%94.491%
499.512%99.998%73.709%97.904%
599.871%100.000%81.174%99.202%
699.966%100.000%86.520%99.697%
799.991%100.000%90.347%99.885%
899.998%100.000%93.088%99.956%

Half-orc Fighter/Thief169.795%92.831%17.741%47.931%
290.877%99.486%32.334%72.888%
397.244%99.963%44.339%85.883%
499.168%99.997%54.214%92.649%
599.749%100.000%62.336%96.173%
699.924%100.000%69.018%98.007%
799.977%100.000%74.515%98.962%
899.993%100.000%79.036%99.460%

Elf Fighter/Magic-user/Thief163.286%90.631%30.791%66.382%
286.521%99.122%52.101%88.698%
395.051%99.918%66.849%96.201%
498.183%99.992%77.057%98.723%
599.333%99.999%84.121%99.571%
699.755%100.000%89.010%99.856%
799.910%100.000%92.394%99.951%
899.967%100.000%94.736%99.984%

Half-elf Fighter/Magic-user/Thief173.268%93.152%33.545%68.110%
292.854%99.531%55.837%89.830%
398.090%99.968%70.652%96.757%
499.489%99.998%80.497%98.966%
599.863%100.000%87.039%99.670%
699.964%100.000%91.387%99.895%
799.990%100.000%94.276%99.966%
899.997%100.000%96.196%99.989%

Elf Magic-user/Thief174.924%93.240%42.928%75.586%
293.712%99.543%67.428%94.039%
398.423%99.969%81.411%98.545%
499.605%99.998%89.391%99.645%
599.901%100.000%93.945%99.913%
699.975%100.000%96.544%99.979%
799.994%100.000%98.028%99.995%
899.998%100.000%98.874%99.999%

Half-elf Magic-user/Thief175.042%93.250%45.393%76.468%
293.771%99.544%70.180%94.463%
398.445%99.969%83.716%98.697%
499.612%99.998%91.108%99.693%
599.903%100.000%95.144%99.928%
699.976%100.000%97.348%99.983%
799.994%100.000%98.552%99.996%
899.998%100.000%99.209%99.999%

Gnome Illusionist/Thief16.269%33.908%0.312%2.749%
212.144%56.319%0.622%5.421%
317.652%71.130%0.932%8.021%
422.814%80.920%1.241%10.549%
527.652%87.389%1.548%13.008%
632.188%91.665%1.855%15.399%
736.439%94.492%2.161%17.724%
840.423%96.359%2.466%19.985%