risk factors

• how to determine lung cancer:

  1. scientists looked at how many cigarettes people smoked everyday and then how many of these people developed lung cancer
  2. looking to see if there was a correlation between lung cancer + smoking
• how did scientists determine a correlation of lung cancer and smoking?

  plotted a scatter graph showing a positive correlation
• how do scientists carry out sampling?

  they sample a group of people and try making conclusions about the whole population - to remove bias they take larger sample as possible