###### Asked in EconomicsModelingNiels BohrMale Models

Economics

Modeling

Niels Bohr

Male Models

# Why are the martingale models less restrictive than the random walk model?

## Answer

###### Wiki User

###### May 03, 2009 1:22AM

The error term in a random walk is assumed to be iid (often white-noise), but the error in a martingale doesn't have to be. If the error is AR(1) however, then the process can't be martingale, as the error in last period is known, and so the current period error is not mean zero anymore. But the error may have second order serial correlation (like an ARCH process), and still be a martingale. The error in a random walk however must be independent of the prior error (at all orders).

## Related Questions

###### Asked in Modeling, London

### Are there any agencies in London?

A La Carte model agency
Asian Runway
Base Models
Beau-Belle Models
Blu Fusion Models
Bookings models
Boss model management
Carpe Diem Model Management
Century Models
Close models
D1 Model Management
Distinct Models
Dynamite Models
Edge Models and Extras Agency
Elegance Models
Elite Model Management London
ENJ Models
Flair Talent Modeling Agency
First model management
FM model agency
Independent models
IMG models
Impact model management
IMM International Model Management
justff model agency
M and P management
Models1
Modelplan
MOT models
nevs models
Next models
Oriental Models UK
Oxygen models
Phoebe Rose Management
Platinum Models
Premier model management
Profile model agency
RAH Productions
Real London Casting
Risque Model Management
Samantha Bond Management
Select model management
Shoop Promotions
Stand Out Model Management
Storm models
Target models
Union model management
United Model Management
Tess Management
W Models

###### Asked in English Language, Technology, The Difference Between

### What is the difference between deterministic and stochastic simulation models?

Any simulation model that does not contain any random or
probabilistic element is called
a deterministic simulation model. The characteristic of this
type of simulation model is
that the output is determined when the set of input elements and
properties in the model
have been specified. For example, a deterministic simulation
model can represent a
complicated system of differential equations.
Many simulation models however, have at least one element that
is random, which gives
rise to the stochastic simulation model. In most simulation
models randomness is
important to mimic the real scenario, for example user
connections to the internet arise
'randomly' when a person pressing a key. However, for any
stochastic simulation model
that has random output, the output (numerical results) can only
be treated as an estimate
of the true output parameters of the model

###### Asked in Science

### Types of scientific models?

###### Asked in Modeling

### Who are Sirena Models?

###### Asked in Modeling

### Give an example of a model?

###### Asked in Cars & Vehicles

### How is physical model different from mathematical model?

A mathematical model is made up of mathematical
equations and data. These models allow you to calculate things such
as how far a car will travel in an hour or how much you could weigh
on the moon. Physical models are models that you
can touch. Toy cars, models of buildings, maps, and globes are all
physical models.