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

What are the advantages of budgetary control, What are the Advantages of bu...

What are the Advantages of budgetary control This budgetary control system helps in fixing the goals for the organization as a whole and concerts efforts are made for its achie

Financial, IF net income totaled $18,000 for one year, beginning assets wer...

IF net income totaled $18,000 for one year, beginning assets were $100.000 and ending assets were $140,000, then Return on Assets for the year as a percentage will be?

Characterize the short run production function of a firm, Question 1: (...

Question 1: (a) ‘The car industry is characterized by broad products differentiation' Analyse the long run situation of a car producer, commenting on profitability and efficien

Explain short term budgets, Explain Short term budgets Short term budge...

Explain Short term budgets Short term budgets: these budgets are generally for one or two years and are in the form of monetary terms. The consumer's good industries like su

Advantages of participatory budgets, Advantages of participatory budgets ...

Advantages of participatory budgets Information from employees most recognizable with each unit’s needs and constraints is included. Knowledge spread amongst numerous lev

Advanced acc, Pike Corporation paid $100,000 for a 10% interest in Salmon C...

Pike Corporation paid $100,000 for a 10% interest in Salmon Corp. on January 1, 2010, when Salmon''s stockholders'' equity consisted of $800,000 of $10 par value common stock and

Help, Sean Corp. issued a $60,000, 10 year bond at the face rate of 8% annu...

Sean Corp. issued a $60,000, 10 year bond at the face rate of 8% annually on 1/1/X0. The market rate was 10%. How much cash will the bond investors receive at the end of the first

Sales, Ask question #MinimumYears Purchase Costs Running cost discount fact...

Ask question #MinimumYears Purchase Costs Running cost discount factor 8% Running cost Savings PVS 0 -7000 -7000 1 2000 0.926 1852 5556 3704 2 2500 0.857 2142.5 5999 3856.5

Constraints, Constraints 1) A constraint of the type ≤ (≥) can be conve...

Constraints 1) A constraint of the type ≤ (≥) can be converted to an equation by adding a slack variable to (subtracting a surplus variable form) the left side of the constrain

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