Explain missing values, Advanced Statistics

Assignment Help:

Missing values: The observations missing from the set of data for some of the reason. In longitudinal studies, for instance, they might occur because subjects drop out of the study completely or do not appear for one or other of scheduled visits or because of the equipment failure. The common causes of subjects prematurely ceasing to participate include the recovery, lack of improvement, the unwanted signs or symptoms that might be related to the investigational treatment, unlikeable study procedures and the intercurrent health problems. Such values greatly complicate number of methods of analysis and simply using those individuals for whom data are complete can be unsatisfactory in number of situations. A distinction can be made between the values missing completely at random (MCAR), missing at random (MAR) and the non-ignorable (or informative).

The MCAR variety arise when the individuals drop out of study in a process which is independent of the observed measurements and those that would have been available had they not been missing both; here the observed values effectively constitute the simple random sample of the values for all study subjects. Random drop-out (MAR) happens when the dropout process depends on the outcomes which have been observed in the past, but given this information is conditionally independent of all future (which is unrecorded) values of the outcome variable following the drop-out. At last, in the case of informative drop-out, the drop-out process depends upon the unobserved values of the result variable. It is the latter which cause most the problems for the analysis of data comprising missing values.


Related Discussions:- Explain missing values

Simplex method, Economic Interpretation of the Optimum Simplex solution

Economic Interpretation of the Optimum Simplex solution

Analysis of variance, Thomas Economic Forecasting, Inc. and Harmon Economet...

Thomas Economic Forecasting, Inc. and Harmon Econometrics have the same mean error in forecasting the stock market over the last ten years. However, the standard deviation for Thom

Observational study, Observational study   is the study in which the object...

Observational study   is the study in which the objective is to discover cause-and-effect relationships but in which it is not feasible to use the controlled experimentation, in th

Explain Grade of membership model, Grade of membership model: This is the ...

Grade of membership model: This is the general distribution free method for the clustering of the multivariate data in which only categorical variables are included. The model ass

Factorization theorem, The theorem relating structure of the likelihood to ...

The theorem relating structure of the likelihood to the concept of the sufficient statistic. Officially the necessary and sufficient condition which a statistic S be sufficient for

EDUC 606, The GRE has a combined verbal and quantitative mean of 1000 and a...

The GRE has a combined verbal and quantitative mean of 1000 and a standard deviation of 200.

Probability., 5. Packages from a machine a normally distributed with a mean...

5. Packages from a machine a normally distributed with a mean 200g and its standard deviation 2grams. Find the probability that a package from the machine weighs a) Less than

Chance events, Chance events : According to the Cicero these are events whi...

Chance events : According to the Cicero these are events which occurred or will occur in ways which are the uncertain-events which may happen, may not happen, or may happen in some

frequentist inference, The approach to statistics based on a frequency vie...

The approach to statistics based on a frequency view of probability in which it is supposed that it is possible to consider an in?nite sequence of the independent repetitions of th

Zero sumgame, Zero sumgame is a game played by the number of persons in wh...

Zero sumgame is a game played by the number of persons in which the winner takes all stakes given by the losers so that the algebraic sum of gains at any stage is zero. Number of

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