Independence of observations, Managerial Accounting

Assignment Help:

Independence of observations

An important assumption for the simple linear regression model is the independence of errors. In many time series models, this assumption is violated because of the correlation of errors in successive observations. This is termed to as autocorrelation.

Autocorrelation occurs if a positive error is followed by another positive error and a negative error is followed by another negative error. If autocorrelation occurs then time should be considered as an important independent variable and therefore time varies analysis should be used.

We can use Durbin Watson ‘D’ statistics to determine whether observations are independent.
D = ∑(ei – ei-1)2
        ∑ei2

Where:

ei is the error in time i
ei-I is the error in time i-I

The Durbin Watson statistics provides a measure of association between successive values of the error term. The computed statistics is compared against two tabulated values du and dl that depend on the desired confidence level of the test and the degrees of freedom of the data.

If the computed Durbin Watson “D” statistics is greater than Du, then we can conclude that there’s no positive correlation between error terms.

If dl ≤ D≤ du then the test is inconclusive and therefore we can neither accept nor reject the null hypothesis.


Related Discussions:- Independence of observations

Hold-up problem or another problem, According to the Philadelphia Inquirer,...

According to the Philadelphia Inquirer, in 2004 the city of Philadelphia planned to spend $14 million to convert the Convention Center into an appropriate venue for the Republican

Motives for holding inventories, MOTIVES FOR HOLDING INVENTORIES If pro...

MOTIVES FOR HOLDING INVENTORIES If production and delivery of goods were instantaneous, there would be no need for inventories. However in reality, the manufacturing and purcha

What is the amount of liabilities, Find the value of the following: a.  ...

Find the value of the following: a.    If the total assets are Rs. 87,000 and the liabilities are Rs. 47,000, find out the amount of capital. b.    If the capital of propriet

What specifically caused your emotional response?, What story or character ...

What story or character in a story generated what Aristotle calls a "catharsis?" Describe your emotional response. What specifically caused your emotional response?

How can improvement in product design - cost reduction, Improvement in prod...

Improvement in product design may result in cost reduction illustrated below: 1) Material cost : change in design of the product may result in saving in material cost. Economi

What is the main purpose of cost centre, Explain the main purpose of cost c...

Explain the main purpose of cost centre The main purpose of cost centre is two fields. 1. Recovery of cost: costs are collected, classified into two field in respect of

Operating cycle period, Period of operating cycle implies that total sum of...

Period of operating cycle implies that total sum of number of days included in the various stages of operation commencing from the purchase of raw materials and ending along with c

Qt, x+2y+3z=6 2x+4y+z=7 3x+2y+9z=14

x+2y+3z=6 2x+4y+z=7 3x+2y+9z=14

Introduction to Management Accounting, What is Costco''s Financial decision...

What is Costco''s Financial decisions, Centralized or decentralized?

Credit information, So as to makes sure that the receivables are collected ...

So as to makes sure that the receivables are collected in occupied and on due date by the customers, prior information of their credit worthiness must be obtainable. This informati

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd