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

Importance of a budget, Importance of a budget A Budget is a plan expre...

Importance of a budget A Budget is a plan expressed in monetary terms. It is prepared prior to the budget period and may show income, expenses and the capital to be used i.e. a

Explain budgetary control according to CIMA, Budgetary control Accordin...

Budgetary control According to CIMA the establishment of budgets relating the responsibilities of executive to the requirement of a policy and the continuous comparison of achi

Stock turnover ratio, opening stock 19000 closing stock 21000 sales 200000 ...

opening stock 19000 closing stock 21000 sales 200000 gross profit 25% on sales calculate stock turnover ratio

Management, Discuss the different roles played by the qualitative and quant...

Discuss the different roles played by the qualitative and quantitative approaches to managerial decision making

Algebraic analysis, ALGEBRAIC ANALYSIS The supposition of linear cost b...

ALGEBRAIC ANALYSIS The supposition of linear cost behavior allows use of straight-line graphs and simple linear algebra in cost-volume study. The net cost is a semi-variable c

What is direct material cost variance, What is Direct material cost varianc...

What is Direct material cost variance It can be defined as the difference between the standard costs of direct material specified and the actual cost of direct material used.

cost per equivalent unit was determined , The Ragan Corporation uses a pro...

The Ragan Corporation uses a process cost system. The company started March with 2,300 units in Work in Process-Dept. A. During the month 4,000 units were started. At the end of th

Explain the techniques of cvp analysis, Techniques of CVP Analysis  The...

Techniques of CVP Analysis  The CVP  analysis deals with the price costs structure and the sales volume and identifies the profit figure with one or other combination of these

Compute the operating cycle, Under this method, approximation is made of pa...

Under this method, approximation is made of payments and cash receipts in the ensuring period. The dissimilarity of these payments and receipts indicates deficiency or surplus of c

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