Derive a regression forecasting equation, Mechanical Engineering

Derive a regression forecasting equation:

The general manager of a company producing road rollers is convinced that the demand for road rollers is associated to the number of road construction tenders issued in the state during the previous years. The past data gathered is shown in the Table.

1957_Derive a regression forecasting equation.png

1. Derive a regression forecasting equation.

2. Estimate the demand for road roller when the number of tenders issued is 28.

3. Calculate the standard deviation of regression and the correlation coefficient.

Solution

 (a)       First of all, it is useful to prepare the following Table.

1848_Derive a regression forecasting equation1.png

n = no. of observations = 8

x = 184 /8 = 23 ;         Y = 80/8 = 10

b = 2146 - 8 (23) (10) / (5006 - 8 (23) (23)) = 0.35

and      a = 10 - 0.395 (23) = 0.91

∴   Y = 0.91 + 0.395 X is the regression forecasting equation.

(b) For       X = 28

Y = 0.91 + 0.395 (28) ≅ 12 road rollers

(c) Standard deviation

[ (∑Y 2  - a ∑Y - b ∑ X Y)/(n-2)] = [950 - (0.9) (80) - (0.395) (2146))/(8-2)](1/2)

= 2.2 road rollers

Correlation coefficient

676_Derive a regression forecasting equation2.png

=  8 (2146) - (184) (80) /{[8 (5006) - (184)2 ] [8 (950) - (80)2 ]}1/ 2

  = 0.90

The value of r is quite close to 1 indicating a very good correlation.

Posted Date: 1/31/2013 6:59:31 AM | Location : United States







Related Discussions:- Derive a regression forecasting equation, Assignment Help, Ask Question on Derive a regression forecasting equation, Get Answer, Expert's Help, Derive a regression forecasting equation Discussions

Write discussion on Derive a regression forecasting equation
Your posts are moderated
Related Questions
What do you mean by thermodynamic equilibrium? Compare irreversible process with reversible process. Give some examples of irreversible process.

Energy - thermodynamics: The energy can be defined as the capacity of doing work. The energy possessed by system may be of two kinds. 1. Stored energy: for example potent

Definition of screw conveyor Screw conveyors belong to the conveyer with traction component. It depends on the shaft with spiral blades in hematic chute to make material move o

First Gear Position : When gear M1 is in mesh with gear C1 then this is first gear drive position. The gear C1 is freely attached to counter shaft, so gear C1 itself cannot rotate

Brazing Vs Welding Following are the differences between brazing and welding. (i)  In brazing, the joint surfaces are not raised to fusion point (or melted) and the joint is

write short note on''coefficient of insensitiveness''of governors.

Safety Functions - Industrial Safety In the statement about safety organization various functions have been mentioned. Yet, a clear description is lacking. Without much elabor

defect of casting

Explain Objectives of Radial drill machine There are many objectives such like, 1.   With the help of angle drill machine, an angle hole can be produced at any angle.  2.

Q. Setting and installations of insulation? The setting and installations of insulation shall be to Specification No. later. The steam drum surfaces shall be insulated with