Case study:

The probability of an individual becoming diseased is the risk. An example comes from a survey of four factories that used acid anhydrides; workers were asked about respiratory problems beginning after employment. Respiratory symptoms were reported by 34 of the 401 subjects. The workers were employed at four different factories, with factory two known to use large amounts of tremolitic anhydride (TMA); 13 cases out of 116 had work-related respiratory symptoms to TMA exposure. To investigate this chemical's relative danger, the risk or odds of workers at factory two can be compared with workers at the other factories. Workers at the other factories are called 'unexposed', and their risk or odds are referred to as 'baseline.' The Investigation of treatment effects can be made similarly by comparing disease probability in treated and untreated patients. The relative risk (RR), also sometimes known as the risk ratio, compares the risk of exposed and unexposed subjects, while the odds ratio (OR) compares odds.

Calculate:

1. The risk of disease

2. The odds of disease.

3. The Relative Risk (RR) & Odd Ratio(OR)

4. Interpret your answers.