Annual incomes for heads of household in a section of a city have approximately a gamma distribution with alpha = 20 and beta = 1000.

a) Find the mean and the variance of these incomes

b) Would you expect to find many incomes in excess of $30,000 in this section of the city?

For a) Mean = (alpha)(beta) = (20)(1000) = 20000

Variance = (alpha)(beta)^2 = (20)(1000)^2 = 20000000

Is this correct?

For b) I'm not sure how to go about this. Any advice?

Thanks!!