The average over the whole set is not a simple average of the individual averages because it is a weighted average of the individual averages. In fitten's example: 10/12 * 1000/10 + 2/12 * 4/2 ...

Using the same $12,000 example, Orman illustrated how this method can result in owning more shares by the end of the year. In ...

In her example, $1,000 per month could result in 107.74 shares instead of 100. At the end of the year, with the ETF at $120 per share, the investment is worth $12,928—higher than the lump-sum ...