My apologies if this is more an "academic" question than an Excel question...

I'm looking to create a probability distribution in Excel. My probability
distribution is similar to a normal distribution, but it's scewed. My data
ranges (for example) from 200 to 800 and has a mean of 400. If my mean were
500, then this would look like a normal curve with 2*stdev of approx 150.
But since the mean is 400, the curve is scewed to the left a bit.

Does anyone have an idea as to what kind of probability distribution I would
use for this? My end result is using the distribution for a Monte Carlo
simulation (which I have all set up in a worksheet).

Thank you.