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

Profile plots, Profile plots  is a technique of representing the multivaria...

Profile plots  is a technique of representing the multivariate data graphically. Each of the observation is represented by a diagram comprising of a sequence of equispaced vertical

Find the expected value of perfect information, You may have the opportunit...

You may have the opportunity to buy some electronic components. These components may be reliable (1) or unreliable (2). The potential pro?ts are £10,000 if the components are rel

Computer-assisted interviews, Computer-assisted interviews : A method or te...

Computer-assisted interviews : A method or technique of interviewing subjects in which the interviewer reads the question from the computer screen instead of the printed page, and

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

Mean-range plot, Mean-range plot   is the graphical tool or device usefu...

Mean-range plot   is the graphical tool or device useful in selecting a transformation in the time series analysis. The range is plotted against the mean for each of the seasona

Advanced managerial statistics, The objective of this assignment is to test...

The objective of this assignment is to test your understanding in the learning outcome (LO2) and learning outcome (LO3) and learning outcome (LO4). 1) This is a grouped assignme

Expected monetary value, Ask quesoil company is considering whether or not ...

Ask quesoil company is considering whether or not to bid for an offshore drilling contract. If they bid, the value would be $600m with a 65% chance of gaining the contract. The com

Queuing, The number of passengers arriving at an airport terminal average 1...

The number of passengers arriving at an airport terminal average 1200 each hour. To process passengers (check in, take luggage, etc) take an average of 6 minutes each. There are

Quality-adjusted survival analysis, Quality-adjusted survival analysis is ...

Quality-adjusted survival analysis is a method for evaluating the effects of treatment on survival which allows the consideration of quality of life as well as the quantity of lif

Distribution free methods, The statistical methods for estimation and infer...

The statistical methods for estimation and inference which are based on a function of sample observations, probability distribution of which does not rely upon a complete speci?cat

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