Medical researchers followed 6272 Swedish men for 30 years to see whether there was any association between the amount of fish in their diet and prostate cancer. A mosaic plot of the results is given. What is the purpose of the study?
1) To determine the effect of fish consumption on prostate cancer risk
2) To investigate the relationship between diet and overall health
3) To compare the incidence of prostate cancer in different countries
4) To analyze the impact of lifestyle factors on cancer development