A 3-year veteran of the local baseball team was calculating his lifetime batting average. The first year he played for half the season and batted .350 (28 hits in 80 at-bats).
The second year he had about twice the number of at-bats and his average was .325. The third year, although he played even more regularly, he was in a slump and batted only .275.
Adding the three season averages and dividing the total by 3, he found his lifetime batting average to be .317. Is this correct? Explain.