Your employer offers you retirement accounts at Vanguard, which has a variety of funds you can choose from. You are thinking about allocating your retirement money among a US equity index fund (symbol VIIIX) and a US bond index fund (symbol VBTIX). The first thing you would like to know is the extent of diversification your portfolio would potentially glean. In other words, you want to have a sense of the dynamic correlation of the two funds over time. Describe