FINANCIAL ESSAY

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SixSigma4.ppt

ANALYZE PHASE

Polytechnic University of Puerto Rico
Department of Industrial Engineering
MMP 6130
Six Sigma

Hypothesis Test of the Variance of a Population

  • Chi-Square Distribution
  • Used when we want to know if the standard deviation or variance of a process is greater, equal, or lower than a specific value.

Example 1

Variance Specifications

Ingredient A = .36 lbs

Ingredient B= .10 lbs

Ingredient C=3.5 lbs

Alpha = 5%

Blending Process
Ingredient A Ingredient B Ingredient C
19.2 lbs 1.2 lbs 140.7 lbs
19.5 lbs 1.4 lbs 139.6 lbs
19.0 lbs 1.6 lbs 137.3 lbs
18.9 lbs 1.4 lbs 142.5 lbs
19.3 lbs 1.5 lbs 138.7 lbs
19.2 lbs 1.4 lbs 139.6 lbs

Hypothesis Test of the Variance of Two Population

  • F-Distribution
  • Used to compare the standard deviation or variance of two processes.
  • If n is the same,
  • If is n not the same,

Example 2

Blending Process
Process A Process B Process C
100 lbs/min 108 lbs/min 109 lbs/min
120 lbs/min 107 lbs/min 108 lbs/min
105 lbs/min 104 lbs/min 110lbs/min
107 lbs/min 110 lbs/min 107 lbs/min
114 lbs/min 110 lbs/min 116 lbs/min
108lbs/min 106 lbs/min 113 lbs/min

Linear Regression

  • Used to find the equation that is closer and most precise to be used as a tool for projection.

  • Objective:
  • Determine the linear function that assimilates to the behavior of the data.

Sum of Minimum Squares

  • Linear Function
  • Independent Variable x

  • Dependent Variable y
  • Variation of the combination of both variables
  • Slope of the Function
  • Intercept in y

Coefficient of Correlation

  • Used to determine the precision of the function with relation to the actual values.

Coefficient of Correlation

  • If r, is near +1 (0.5 and 1) therefore there is a strong linear relationship between the dependent and independent variable with a positive slope.

  • If r, is near -1 (-0.5 and -1) therefore there exists a strong linear relationship between the dependent and independent variable with a negative slope.

  • If r, is near 0 (-0.49 and .49) therefore there is no linear relationship. This means that the value of Y does not depend of X.

Anova

Variation Form Sum of the Squares Liberty Degrees Mean Square Value of Fexp
Regression 1
Error n-2

Example 3

Blending Process
Temperature Output
80° 108 lbs/min
79° 107 lbs/min
75° 104 lbs/min
82° 110 lbs/min
84° 110 lbs/min
80° 106 lbs/min

Multiple Regression

  • When we have a process where the dependent variable follows a linear behavior that the independent variable changes it is possible to determine the linear function it represents.

Multiple Regression

N Σ X Σ Z Σ Y

Σ X Σ X^2 Σ XZ Σ XY  

Σ Z Σ XZ Σ Z^2 Σ ZY

Multiple Regression

Usando la tecnica de Kramer de matrices, sacamos cuatro determinandes:

  • I A I Determinante de la matriz original
  • I a I Determinante de la matriz impactada por el Intercepto.
  • I x I Determinante de la matriz impactada por pendiente en X.
  • I z I Determinante de la matriz impactada por pendiente en Z.

A = Intercepto en Y = IaI / IAI

Bx= Pendiente en X = IxI / IAI entonces, Y = a + x(bx) + z(bz)

Bz= Pendiente en Z = IzI / IAI

Multiple Regression

ANOVA: Syy = Σ Y2 - (Σ Y)2

n

SSR = ΣBj Gj - (Σ Y)2

n

SSE = Syy- SSR

Se2 = SSE / (n-k-1)

Ho: Regresión no significativa

H1: Regresión significativa

F exp: SSR / k

SSE / (n-k-1)

Example 4

Weight(lbs) Volume(cft) Output

10 5 12

9 4 15

11 5 14

13 5 16

12 6 11

Two Factor Design

  • Used to determine if their exists or not any relationship between more than one independent or dependent variable.

  • This analysis could measure if the dependent variable could have been affected with two independent variables.

Two Factor Design

Where:

  • a=# of treatments
  • b=# of blocks
  • n=# repetitions
  • Ti= Total treatments
  • Tij= Total of treatments

per treatment/block

  • T=total of all the results

Two Factor Design

  • To convert the sum of minimum squares into a variance

Two Factor Design

Example 5

Solution Quantity Product Yield Process Temperature
80°cl 85°cl 90°cl
1.2 gr 95 93 91 93 92 90
1.6 gr 94 95 90 91 90 91
2.0 gr 96 92 92 93 89 92

(

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