"I'm not sure what numbers from the Texas spreadsheets you used in your previous post to determine the chance of a roll but what do you think are the chances we see another 2 billion jackpot? "
There's a worksheet for every drawing, and you'll find a link to it on the page that shows the current advertised jackpot. Somewhere around noon on the day of the drawing (or Friday for Saturday's PB jackpot) they add the next jackpot if it rolls.
https://www.texaslottery.com/export/sites/lottery/Games/Powerball/Estimated_Jackpot.html
https://www.texaslottery.com/export/sites/lottery/Games/Mega_Millions/Estimated_Jackpot.html
There are a bunch of variables that affect the chance, so I'll make some assumptions. First, I'll figure tomorrow's jackpot ends up at exactly $1 billion and rolls. I'll also figure that the interest rate remains the same and every $100 million of advertised jackpot is $45.3 million cash. Then I'll figure the rolls (if they happen) are to 1.15 >1.35 > 1.65 and 2.00 billion. Skipping some math, that means selling about 101, 135, 203, and 237 million tickets. The chances of a rollover for those drawings would then be 0.708, 0.63, 0.499, and 0.457. Multiply the first 3 together and the chance of rolling and reaching $2 billion is 0.2226 or 22.3%. The chance of also rolling the 4th time is 10.2%. One of the biggest variables is what the actual jackpots are. If we get 3 rolls after Saturday and the 4th jackpot is to a bit more than 2 billion then the chance is 22.3% because it only needs to roll past 1.65 and the mystery is whether or not it's won at the first jackpot over 2 billion. If 3 rolls gets it to anything under 2 billion we'd need that 4th rollover to get past it.
"Even with 254,931 Lottery Post members we are yet to have a second prize jackpot winner. "
If there were actually that many members and they each played once per week they would collectively buy 13,256,412 tickets per year. Probability would then suggest 1 second place winner 48 weeks or so, except that a lot of those tickets would be from the smaller subset of possible combinations using only calendar numbers. Of course there aren't that many members now even if you count people who signed up and simply haven't come back. A substantial portion of those "members" have died and won't be buying tickets no matter how big the jackpot gets. That said, for as long as LP has been around there's very likely somebody who signed up at some point and has won a 2nd place prize unless most of them have stuck strictly to games besides PB or MM.