Estadistica

Un artículo publicado en la revista Emprendedores, indica una toma de datos sobre el octanaje de varias mezclas de gasolina:
# | Intervalos | fi | Xi | Xi-X | fi.Xi-X | fi.Xi2 |
1 | 83 – 85 | 3| 84 | 5.88 | 17.64 | 21168 |
2 | 85 – 87 | 3 | 86 | 3.88 | 11.64 | 22188 |
3 | 87 – 89 | 12 | 88 | 1.88 | 22.56 | 92928 |
4 | 89 – 91 | 14 | 90 | 0.12 | 1.68 | 113400 |
5 | 91 – 93 | 12 | 92| 2.12 | 25.44 | 101568 |
6 | 93 – > | 6 | 94 | 4.12 | 24.72 | 53016 |
| | | | | =103.68 | =404268 |

X=89.88 DM= 2,07 σ=7.09
X =90 Ico(DM)= 87.81 , 91.95
X=90 Ico (σ)= 87.22 , 92.54
Distancia media
DM= fi.Xi-XN
DM=103.6850=2.07 oct.
Intervalo de confianza
Ico=X - + DM
Ico=89 ± 2.07
Ico=Lic,Lsc
Lic=X-DM 89.88-2.07=87.81 oct.
Lsc=X +DM 89.88+2.07=91.95 oct.
Ico=87.81 ,91.95oct

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-DM
87.81
+DM
91.95
Lic
Lsc
Ico
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Varianza
σ2 =∑fi.Xi2-N.X2N-1

σ2 =404268-403920.7250-1 = 7.09
Desviación Típica
σ=7.09 = ±2.66
Ico=Lic,Lsc
Lic=X -σ 89.88-2.66=87.22 oct.
Lsc=X +σ 89.88+2.66=92.54oct.
Ico=87.22 ,92.54oct

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-DM
87.22
+DM
92.54
Lic
Lsc
Ico
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Pearson
P=X-X.3σP=89.88-90.32.66= -0.14
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P(-)
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