1) Explain the difference between prospective and retrospective studies. Compare the data collection process.Which totals in the contingency table are controlled by the experimenter in each of the...

1) Explain the difference between prospective and retrospective studies. Compare the data collection process.Which totals in the contingency table are controlled by the experimenter in each of the cases?
2) Explain the idea of the decomposition of contingency tables: when we use this technique and what it can provide.