I have following diets: 30P9L, 30P7L, 35P7L, 35P9L, 35P12L, 40P12L. P represent Protein and L is lipid. In such experimental design, can I use two-way ANOVA?
I am not sure I have enough information to answer your question. Here are some questions for you that would help me respond. What, exactly are your two independent variables--diet and P/L? What is your dependent variable? Is it continuous? Is it univariate? How large a sample do you expect to collect? What is your sampling plan? It is possible that your research questions would reveal the answers to my questions if I had them.