Anàlisi de Dades Experimentals
© Antoni Amengual Colom. Departament de Física, Universitat de les Illes Balears.
Versió 1.0 publicada al setembre de 2013. DL: PM 860-2013.
Apèndix
Chi-quadrat. Taules i gràfics
Introducció «
Els valors de les probabilitats donats a continuació s'expliquen en aquest tema.
Pr(χ2 ≥ χ02): Taules «

Figura 1. L'àrea de color verd dóna la probabilitat que chi quadrat sigui més gran que el valor χ02.
Taules de la probabilitat que χ2 sigui més gran que χ02 segons el nombre de graus de llibertat m. S'ha de notar que les entrades a la primera columna són per a χ2/m.
Graus de llibertat de 1 a 10 »
| m=1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
0.0 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
0.1 | 75.2 | 90.5 | 96.0 | 98.2 | 99.2 | 99.6 | 99.8 | 99.9 | 100.0 | 100.0 |
0.2 | 65.5 | 81.9 | 89.6 | 93.8 | 96.3 | 97.7 | 98.6 | 99.1 | 99.4 | 99.6 |
0.3 | 58.4 | 74.1 | 82.5 | 87.8 | 91.3 | 93.7 | 95.4 | 96.6 | 97.5 | 98.1 |
0.4 | 52.7 | 67.0 | 75.3 | 80.9 | 84.9 | 87.9 | 90.3 | 92.1 | 93.6 | 94.7 |
0.5 | 48.0 | 60.7 | 68.2 | 73.6 | 77.6 | 80.9 | 83.5 | 85.7 | 87.6 | 89.1 |
0.6 | 43.9 | 54.9 | 61.5 | 66.3 | 70.0 | 73.1 | 75.6 | 77.9 | 79.8 | 81.5 |
0.7 | 40.3 | 49.7 | 55.2 | 59.2 | 62.3 | 65.0 | 67.2 | 69.2 | 71.0 | 72.5 |
0.8 | 37.1 | 44.9 | 49.4 | 52.5 | 54.9 | 57.0 | 58.7 | 60.3 | 61.6 | 62.9 |
0.9 | 34.3 | 40.7 | 44.0 | 46.3 | 48.0 | 49.4 | 50.5 | 51.5 | 52.4 | 53.2 |
1.0 | 31.7 | 36.8 | 39.2 | 40.6 | 41.6 | 42.3 | 42.9 | 43.3 | 43.7 | 44.0 |
1.1 | 29.4 | 33.3 | 34.8 | 35.5 | 35.8 | 35.9 | 36.0 | 35.9 | 35.9 | 35.8 |
1.2 | 27.3 | 30.1 | 30.8 | 30.8 | 30.6 | 30.3 | 29.9 | 29.4 | 29.0 | 28.5 |
1.3 | 25.4 | 27.3 | 27.2 | 26.7 | 26.1 | 25.3 | 24.6 | 23.8 | 23.1 | 22.4 |
1.4 | 23.7 | 24.7 | 24.1 | 23.1 | 22.1 | 21.0 | 20.0 | 19.1 | 18.2 | 17.3 |
1.5 | 22.1 | 22.3 | 21.2 | 19.9 | 18.6 | 17.4 | 16.2 | 15.1 | 14.1 | 13.2 |
1.6 | 20.6 | 20.2 | 18.7 | 17.1 | 15.6 | 14.3 | 13.0 | 11.9 | 10.9 | 9.96 |
1.7 | 19.2 | 18.3 | 16.5 | 14.7 | 13.1 | 11.6 | 10.4 | 9.28 | 8.30 | 7.44 |
1.8 | 18.0 | 16.5 | 14.5 | 12.6 | 10.9 | 9.48 | 8.25 | 7.19 | 6.28 | 5.50 |
1.9 | 16.8 | 15.0 | 12.7 | 10.7 | 9.07 | 7.68 | 6.51 | 5.54 | 4.72 | 4.03 |
2.0 | 15.7 | 13.5 | 11.2 | 9.16 | 7.52 | 6.20 | 5.12 | 4.24 | 3.52 | 2.93 |
2.1 | 14.7 | 12.2 | 9.79 | 7.80 | 6.22 | 4.98 | 4.00 | 3.23 | 2.61 | 2.11 |
2.2 | 13.8 | 11.1 | 8.58 | 6.63 | 5.14 | 4.00 | 3.12 | 2.44 | 1.92 | 1.51 |
2.3 | 12.9 | 10.0 | 7.52 | 5.63 | 4.23 | 3.20 | 2.42 | 1.84 | 1.41 | 1.07 |
2.4 | 12.1 | 9.07 | 6.58 | 4.77 | 3.48 | 2.55 | 1.87 | 1.38 | 1.02 | 0.76 |
2.5 | 11.4 | 8.21 | 5.76 | 4.04 | 2.85 | 2.03 | 1.44 | 1.03 | 0.74 | 0.53 |
2.6 | 10.7 | 7.43 | 5.03 | 3.42 | 2.34 | 1.61 | 1.11 | 0.77 | 0.54 | 0.37 |
2.7 | 10.0 | 6.72 | 4.40 | 2.89 | 1.91 | 1.27 | 0.85 | 0.57 | 0.39 | 0.26 |
2.8 | 9.43 | 6.08 | 3.84 | 2.44 | 1.56 | 1.00 | 0.65 | 0.42 | 0.28 | 0.18 |
2.9 | 8.86 | 5.50 | 3.36 | 2.06 | 1.27 | 0.79 | 0.50 | 0.31 | 0.20 | 0.12 |
3.0 | 8.33 | 4.98 | 2.93 | 1.74 | 1.04 | 0.62 | 0.38 | 0.23 | 0.14 | 0.09 |
3.1 | 7.83 | 4.50 | 2.56 | 1.46 | 0.84 | 0.49 | 0.29 | 0.17 | 0.10 | 0.06 |
3.2 | 7.36 | 4.08 | 2.23 | 1.23 | 0.68 | 0.38 | 0.22 | 0.12 | 0.07 | 0.04 |
3.3 | 6.93 | 3.69 | 1.94 | 1.03 | 0.56 | 0.30 | 0.16 | 0.09 | 0.05 | 0.03 |
3.4 | 6.52 | 3.34 | 1.69 | 0.87 | 0.45 | 0.23 | 0.12 | 0.07 | 0.03 | 0.02 |
3.5 | 6.14 | 3.02 | 1.48 | 0.73 | 0.36 | 0.18 | 0.09 | 0.05 | 0.02 | 0.01 |
3.6 | 5.78 | 2.73 | 1.29 | 0.61 | 0.29 | 0.14 | 0.07 | 0.03 | 0.02 | 0 |
3.7 | 5.44 | 2.47 | 1.12 | 0.51 | 0.24 | 0.11 | 0.05 | 0.02 | 0.01 | 0 |
3.8 | 5.13 | 2.24 | 0.97 | 0.43 | 0.19 | 0.09 | 0.04 | 0.02 | 0 | 0 |
3.9 | 4.83 | 2.02 | 0.85 | 0.36 | 0.16 | 0.07 | 0.03 | 0.01 | 0 | 0 |
4.0 | 4.55 | 1.83 | 0.74 | 0.30 | 0.12 | 0.05 | 0.02 | 0 | 0 | 0 |
4.1 | 4.29 | 1.66 | 0.64 | 0.25 | 0.10 | 0.04 | 0.02 | 0 | 0 | 0 |
4.2 | 4.04 | 1.50 | 0.56 | 0.21 | 0.08 | 0.03 | 0.01 | 0 | 0 | 0 |
4.3 | 3.81 | 1.36 | 0.49 | 0.18 | 0.07 | 0.02 | 0 | 0 | 0 | 0 |
4.4 | 3.59 | 1.23 | 0.42 | 0.15 | 0.05 | 0.02 | 0 | 0 | 0 | 0 |
4.5 | 3.39 | 1.11 | 0.37 | 0.12 | 0.04 | 0.01 | 0 | 0 | 0 | 0 |
4.6 | 3.20 | 1.01 | 0.32 | 0.10 | 0.03 | 0.01 | 0 | 0 | 0 | 0 |
4.7 | 3.02 | 0.91 | 0.28 | 0.09 | 0.03 | 0 | 0 | 0 | 0 | 0 |
4.8 | 2.85 | 0.82 | 0.24 | 0.07 | 0.02 | 0 | 0 | 0 | 0 | 0 |
4.9 | 2.69 | 0.74 | 0.21 | 0.06 | 0.02 | 0 | 0 | 0 | 0 | 0 |
5.0 | 2.53 | 0.67 | 0.18 | 0.05 | 0.01 | 0 | 0 | 0 | 0 | 0 |
5.1 | 2.39 | 0.61 | 0.16 | 0.04 | 0.01 | 0 | 0 | 0 | 0 | 0 |
5.2 | 2.26 | 0.55 | 0.14 | 0.03 | 0 | 0 | 0 | 0 | 0 | 0 |
5.3 | 2.13 | 0.50 | 0.12 | 0.03 | 0 | 0 | 0 | 0 | 0 | 0 |
5.4 | 2.01 | 0.45 | 0.10 | 0.02 | 0 | 0 | 0 | 0 | 0 | 0 |
5.5 | 1.90 | 0.41 | 0.09 | 0.02 | 0 | 0 | 0 | 0 | 0 | 0 |
5.6 | 1.80 | 0.37 | 0.08 | 0.02 | 0 | 0 | 0 | 0 | 0 | 0 |
5.7 | 1.70 | 0.33 | 0.07 | 0.01 | 0 | 0 | 0 | 0 | 0 | 0 |
5.8 | 1.60 | 0.30 | 0.06 | 0.01 | 0 | 0 | 0 | 0 | 0 | 0 |
5.9 | 1.51 | 0.27 | 0.05 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6.0 | 1.43 | 0.25 | 0.04 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6.1 | 1.35 | 0.22 | 0.04 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6.2 | 1.28 | 0.20 | 0.03 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6.3 | 1.21 | 0.18 | 0.03 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6.4 | 1.14 | 0.17 | 0.02 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6.5 | 1.08 | 0.15 | 0.02 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6.6 | 1.02 | 0.14 | 0.02 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6.7 | 0.96 | 0.12 | 0.02 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Graus de llibertat de 11 a 20 »
| m=11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
0.0 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
0.1 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
0.2 | 99.8 | 99.8 | 99.9 | 99.9 | 100.0 | 100.0 | 100.0 | 100.0 | 100 | 100 |
0.3 | 98.6 | 99.0 | 99.2 | 99.4 | 99.6 | 99.7 | 99.7 | 99.8 | 99.9 | 99.9 |
0.4 | 95.7 | 96.4 | 97.1 | 97.6 | 98.0 | 98.3 | 98.6 | 98.8 | 99.0 | 99.2 |
0.5 | 90.5 | 91.6 | 92.6 | 93.5 | 94.2 | 94.9 | 95.5 | 96.0 | 96.4 | 96.8 |
0.6 | 83.0 | 84.4 | 85.6 | 86.7 | 87.8 | 88.7 | 89.5 | 90.3 | 91.0 | 91.6 |
0.7 | 74.0 | 75.3 | 76.5 | 77.7 | 78.7 | 79.7 | 80.6 | 81.5 | 82.3 | 83.0 |
0.8 | 64.0 | 65.1 | 66.1 | 67.0 | 67.9 | 68.7 | 69.5 | 70.3 | 71.0 | 71.7 |
0.9 | 53.9 | 54.6 | 55.2 | 55.8 | 56.4 | 56.9 | 57.4 | 57.9 | 58.3 | 58.7 |
1.0 | 44.3 | 44.6 | 44.8 | 45.0 | 45.1 | 45.3 | 45.4 | 45.6 | 45.7 | 45.8 |
1.1 | 35.6 | 35.5 | 35.3 | 35.1 | 35.0 | 34.8 | 34.6 | 34.4 | 34.2 | 34.1 |
1.2 | 28.0 | 27.6 | 27.1 | 26.7 | 26.3 | 25.8 | 25.4 | 25.0 | 24.6 | 24.2 |
1.3 | 21.7 | 21.0 | 20.4 | 19.8 | 19.2 | 18.6 | 18.1 | 17.6 | 17.1 | 16.6 |
1.4 | 16.5 | 15.7 | 15.0 | 14.3 | 13.7 | 13.1 | 12.5 | 12.0 | 11.4 | 10.9 |
1.5 | 12.4 | 11.6 | 10.8 | 10.2 | 9.53 | 8.95 | 8.41 | 7.90 | 7.43 | 6.99 |
1.6 | 9.13 | 8.38 | 7.70 | 7.08 | 6.51 | 5.99 | 5.52 | 5.09 | 4.69 | 4.33 |
1.7 | 6.67 | 5.99 | 5.38 | 4.84 | 4.36 | 3.93 | 3.55 | 3.20 | 2.89 | 2.61 |
1.8 | 4.82 | 4.23 | 3.71 | 3.26 | 2.87 | 2.53 | 2.23 | 1.97 | 1.74 | 1.54 |
1.9 | 3.44 | 2.95 | 2.53 | 2.17 | 1.86 | 1.60 | 1.38 | 1.19 | 1.03 | 0.89 |
2.0 | 2.44 | 2.03 | 1.70 | 1.42 | 1.19 | 1.00 | 0.84 | 0.71 | 0.59 | 0.50 |
2.1 | 1.71 | 1.39 | 1.13 | 0.92 | 0.75 | 0.61 | 0.50 | 0.41 | 0.34 | 0.28 |
2.2 | 1.19 | 0.94 | 0.75 | 0.59 | 0.47 | 0.37 | 0.30 | 0.24 | 0.19 | 0.15 |
2.3 | 0.82 | 0.63 | 0.49 | 0.38 | 0.29 | 0.22 | 0.17 | 0.13 | 0.10 | 0.08 |
Graus de llibertat de 21 a 30 »
| m=21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
0.0 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
0.1 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
0.2 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
0.3 | 99.9 | 99.9 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100 | 100 |
0.4 | 99.3 | 99.4 | 99.5 | 99.6 | 99.7 | 99.7 | 99.8 | 99.8 | 99.8 | 99.9 |
0.5 | 97.2 | 97.5 | 97.7 | 98.0 | 98.2 | 98.4 | 98.6 | 98.7 | 98.9 | 99.0 |
0.6 | 92.2 | 92.7 | 93.2 | 93.7 | 94.1 | 94.5 | 94.9 | 95.2 | 95.6 | 95.9 |
0.7 | 83.8 | 84.5 | 85.1 | 85.7 | 86.3 | 86.8 | 87.4 | 87.9 | 88.3 | 88.8 |
0.8 | 72.3 | 72.9 | 73.5 | 74.1 | 74.7 | 75.2 | 75.7 | 76.2 | 76.7 | 77.2 |
0.9 | 59.2 | 59.6 | 59.9 | 60.3 | 60.7 | 61.0 | 61.4 | 61.7 | 62.0 | 62.3 |
1.0 | 45.9 | 46.0 | 46.1 | 46.2 | 46.2 | 46.3 | 46.4 | 46.4 | 46.5 | 46.6 |
1.1 | 33.9 | 33.7 | 33.5 | 33.3 | 33.1 | 33.0 | 32.8 | 32.6 | 32.4 | 32.3 |
1.2 | 23.9 | 23.5 | 23.1 | 22.8 | 22.4 | 22.1 | 21.8 | 21.4 | 21.1 | 20.8 |
1.3 | 16.1 | 15.7 | 15.2 | 14.8 | 14.4 | 14.0 | 13.6 | 13.3 | 12.9 | 12.6 |
1.4 | 10.5 | 10.0 | 9.61 | 9.20 | 8.82 | 8.46 | 8.11 | 7.78 | 7.46 | 7.16 |
1.5 | 6.57 | 6.19 | 5.83 | 5.49 | 5.17 | 4.88 | 4.60 | 4.34 | 4.09 | 3.86 |
1.6 | 4.00 | 3.69 | 3.41 | 3.15 | 2.92 | 2.70 | 2.50 | 2.31 | 2.14 | 1.98 |
1.7 | 2.36 | 2.14 | 1.93 | 1.75 | 1.59 | 1.44 | 1.30 | 1.18 | 1.07 | 0.97 |
1.8 | 1.36 | 1.20 | 1.07 | 0.94 | 0.84 | 0.74 | 0.66 | 0.58 | 0.52 | 0.46 |
1.9 | 0.76 | 0.66 | 0.57 | 0.49 | 0.43 | 0.37 | 0.32 | 0.28 | 0.24 | 0.21 |
Pr(χ2 ≥ χ02): Gràfics «
Figura 2. Probabilitat que χ-quadrat sigui més gran que un valor donat segons el nombre de graus de llibertat g.
Taules dels valors de probabilitat 5 % i 1 % «

Pr(χ2 ≥ λ5) = 0.05,
Pr(χ2 ≥ λ1) = 0.01.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 3.84 | 5.99 | 7.81 | 9.49 | 11.1 | 12.6 | 14.1 | 15.5 | 16.9 | 18.3 |
| 6.63 | 9.21 | 11.3 | 13.3 | 15.1 | 16.8 | 18.5 | 20.1 | 21.7 | 23.2 |
| 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| 19.7 | 21.0 | 22.4 | 23.7 | 25.0 | 26.3 | 27.6 | 28.9 | 30.1 | 31.4 |
| 24.7 | 26.2 | 27.7 | 29.1 | 30.6 | 32.0 | 33.4 | 34.8 | 36.2 | 37.6 |
| 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
| 32.7 | 33.9 | 35.2 | 36.4 | 37.7 | 38.9 | 40.1 | 41.3 | 42.6 | 43.8 |
| 38.9 | 40.3 | 41.6 | 43. | 44.3 | 45.6 | 47.0 | 48.3 | 49.6 | 50.9 |
| 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 |
| 45.0 | 46.2 | 47.4 | 48.6 | 49.8 | 51.0 | 52.2 | 53.4 | 54.6 | 55.8 |
| 52.2 | 53.5 | 54.8 | 56.1 | 57.3 | 58.6 | 59.9 | 61.2 | 62.4 | 63.7 |
Taula 1. Valors de les variables λ5 i λ1 definides en el text en funció del nombre de graus de llibertat.



