STATS 101, min + max divided by 2 doesn't equal to average

Last night we were having some problems with drilling and the mud engineer called the cabin for some numbers. Since I don't speak Portuguese, I got the goofy directional driller to explain to the mud engineer about min/max and average ECD over the phone. There was a long discussion about it and I was puzzled on what they were talking about since it was just simple statistic. He was writing down "the formula" while he was explaining as I was watching (since I didn't understand a word of Portuguese). The formula went, "min + max / 2 = FUCK YOU!"

He hung up the phone after that, appeared mad, and turned to me, "The mud engineer STUPID MAN!" in his heavy Brazilian Portuguese accent.

The paper was laying on the table and my counterpart for day shift looked puzzled and asked me about "min + max / 2 = FUCK YOU?"

Yes, the mud engineer was a dumbass. If you think that he's right, go take STATS 101 to avoid being a dumbass.