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

Duffy tol and stamping, What are the objectives of excellence teams and min...

What are the objectives of excellence teams and minicompanies? Did the companies achieve these objectives?estion #Minimum 100 words accepted#

Estimate the labor cost, The Knapp Company needs to predict the labor cost ...

The Knapp Company needs to predict the labor cost in producing small carrot patch dolls. The following production information is available: Year Dolls Pr

Correlation coefficient, Correlation coefficient (r) Correlation coeffi...

Correlation coefficient (r) Correlation coefficient measures the degree of association between two variables such as the cost and the activity level. r = nΣxy   -  Σx  Σy

Total annual inventory cost , Ross White's machine shop uses 2,500 brackets...

Ross White's machine shop uses 2,500 brackets during the course of a year, and this usage is relatively constant by the year. These brackets are purchased from a supplier 100 miles

#title.advance accounting research on companies., do you make assignments o...

do you make assignments on Advance Accounting subjects

Strategic plan, How to write introduction on strategy plan

How to write introduction on strategy plan

Various types of short term investment opportunities, The subsequent short-...

The subsequent short-term investment opportunities are obtainable to companies in India to invest their temporary cash excess. a) Treasury Bills: Treasury Bills are short-term

Assgnment, 1. Calculate the manufacturing costs for the year. 2. Prepare a ...

1. Calculate the manufacturing costs for the year. 2. Prepare a statement of cost of goods manufactured. 3. Prepare an income statement (assume an income tax 25%)

Evaluate consumer surplus and the average price, Suppose the consumer is at...

Suppose the consumer is at coffee shop 2. Coffee shop 2 provides unlimited cups of coffee for the price of $9.00 per day. - How many cups would she drink a day and how much woul

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