Question

1. Explain the differences among ‘no association’, ‘negative association’, and positive association’. Provide a specific example of a measure of association (RR, OR, etc.) for each of these and provide a proper interpretation for each.

Answer 1

Positive association:

When increase ( or decrease) in value of one variable tend increase ( or decrease) in value of other variable then we say there is positive association between these two variables.

It means both the variables change in same direction.

Ex. Height and weight of a person.

If height of a person increases then its weight also increases.

Negative association:

When increase (or decrease) in the value of one variable tend to decrease (or increase) in the value of other variable then we say that these two variables are negatively associated.

Here change in the variable occur in opposite directions.

Ex. Price and demand.

When price increases then demand automatically decreases and vice versa.

No association:

If change in one variable doesn't affect the other variable then we say there is no association between these two variables.

Ex. Beauty and intelligence.