What kind of knowledge level does the mathematical content in market research and forecast need? Is junior high school math okay?
In fact, junior high school can basically cope, but if it involves some statistical knowledge, you may need some knowledge of probability statistics in senior high school, but I believe you should find some similar books to make up the basic knowledge. The problem should not be big. After all, market research still uses some basic concepts, and advanced mathematical knowledge is unlikely to be involved. Come on!