When studying diseases and assumptions, always

It is involved in two types of variables, one of which is subject to

Another type of variable, the former is called dependence or

The response variable is called an argument or interpretation variable.

Disease is a response variable in epidemiological studies,

And various cause factors are interpreted variables.

ƒ If you study the effects of cat dry feed on urinary gatter aspiral disease,

Cat feed is interpreted variables, and urinary tone disease should be

Answer variable.

Study the relationship between disease and hypothesis,

It is to study response variables and interpretation variables.

Inter-contact.

The so-called contact is the degree of dependence or independence between two variables.

ƒ Contact is divided into non-statistical contacts and statistical links to two categories.

ƒ (1) Non Statistical disease and hypothesis

Non-statistical links between etiology factors are caused by opportunities

Contact, that is, the disease and hypothesis cause

The frequency of life is not larger than the probability that occurs.

For example, from some eye-catching inflammation, Isolation

Cat isotonic, indicating the conjunctivitis and support of these cats

There is a connection between the body.

ƒ But research shows that from 80% obviously normal cats

This kind of mycoplasma is left. This finding showed that the film

ƒ (2) Statistical Association

Disease and hypothesis factors have more than even

However, the expected frequency occurred together, then there is

Positive statistics contact.

But statistical contact is not necessarily a cause.

Even in a careful design, trying to build

Fruit relationship, not all statistics from the disease

The factors of the system are causal.