How are gas prices tracked?
Question: When you have an article reporting the average price of a gallon of gasoline, is the average for regular, a simple average of the prices for three grades, or a weighted average accounting for the different market shares for the three grades? -- Dave Wordkinger, Medical Lake
Answer: According to the local office of the AAA, when that organization releases gas-price trends, it's always based on the price of regular unleaded. We recently ran an article about gas prices in California based on data from the Energy Information Administration, a unit of the Department of Energy. According to their Web site, that average also is based on a gallon of regular unleaded. More information about gas (and diesel) prices is available from that Web site. -- Addy Hatch, business editor