3. As part of a research project into the role played by cholesterol in the development of heart disease a random sample of 100 patients was put on a special fish-based diet. A different random sample of 80 patients was kept on a standard high-protein low-fat diet. After several weeks their blood cholesterol was measured and the results summarised in the table below.

1. Stating your hypotheses clearly and using a \(5 \%\) level of significance, test whether or not the special diet is more effective in reducing blood cholesterol levels than the standard diet.
2. Explain briefly any assumptions you made in order to carry out this test.