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.


 (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
Prove that energy is a property of system

STEP S FOR SOLVING PROBLEM FOR FINDING POWER: 1. Use formula stress (s) = force (Maximum Tension)/Area Where; Area = b.t that is, Tmax = σ.b.t 2. Unit mass (m) = r.b.t.

Explain the Importance of jigs and fixtures: Enhance productivity. Rapid production work. Reduces manufacturing costs. Complex and heavy components can be

Q. Show Space Considerations for plant? There are particular spacing constraints which need particular care and attention when optimizing the layout area utilization in both ne

Types of stresses: In general stress is divided in to three group as: various types of stresses may be classified as: 1. Simple or direct stress (Tension, Compressi

A vertical petrol engine 100mm diameter and 120mm stroke has a connecting rod 250mm long. The mass of the  piston is 1.1kg. The speed is 2000 r.p.m. On the expansion stroke with a

Project Quality Plan Design verification requirements for a project are to be established in the Quality Plan sub-section of the Project Execution Plan. The Lead Mechanical E

how to design and fabricate wilson hartnell governor?

1) Figure shows a thin Aluminium structural beam use in an aircraft structure.  Using the stiffness method, determine the BM and Shear force of the two elements of the thin beam sh

Q. Portable Gas Cylinders - Handling of Hazardous? Portable Gas Cylinders Portable gas cylinders are vulnerable to fire exposure when located in process areas. Depending on l