On 1st January 2000, there were 1000 people in Britain (population 50 million) who had osteosarcoma. During the year, 200 new cases of osteosarcoma were diagnosed and 75 patients died. Of the 75 patients who died, 50 died of disease and 25 died from other causes. The population remained stable during the year.
In a cross-sectional study, radiographs were taken of 500 wrists. A radiologist reviewed all radiographs and made a diagnosis of Kienböck’s disease in 15 subjects. To determine if negative ulnar variance was a risk factor for Kienböck’s disease, all wrists were also examined for negative ulnar variance. Out of the 500 wrists, the radiologist found 150 cases of negative ulnar variance. 12 of the subjects with negative ulnar variance had Kienböck’s disease.
The Titanic sank in 1912 on its maiden voyage. There were 2223 people on board. Of these, 1683 were men; the rest were women and children. 1517 people died, of whom 1347 were men.
- The absolute risk of dying for men and women / children
- The odds for men and women / children
- The odds ratio with 95% confidence interval
- The odds ratio with 99% confidence interval
The majority of people who died at the Titanic disaster were passengers. There were 1324 passengers on board. 710 of these were third class passengers, the rest were first or second class passengers. 536 (75 %) of the third class passengers died, whilst 318 of the first and second class passengers survived.
- Calculate the absolute risk of dying for third class passengers and first / second class passengers
- Calculate the odds for third class passengers and first / second class passengers
- Calculate the odds ratio with 95% confidence interval
A case control study of prostate cancer risk in patients with male pattern baldness has been performed. There were 149 patients with prostate cancer, of whom 46 had male pattern baldness. The control group consisted of 125 patients who did not have prostate cancer. Of these 125 patients, 72 had male pattern baldness.
- Calculate the odds on prostate cancer for bald and ‘hairy’ patients.
- What is the odds ratio (95% confidence interval)