There was a puzzle given on the Skeptics Guide podcast on 9/13/2006 and the solution they gave the next week bothered me. (They said it was ambiguous depending on how the question was phrased).

I was googling around looking for other references to this problem and found these two:

Marilyn Ignores the Obvious Regarding Probability of Boys by Herb Weiner

Eldon Moritz rebutal to Marilyn vos Savant

After reading Eldon's page, I realized how to rephrase the question to show the right process. Everyone is focusing on the 4 possibilities of children so let's set up the problem that way.

There are 4 women and 4 children walking through the park. The first woman (BB) has a boy with her and a boy at home, the second woman (BG) has a boy with her and a boy at home, the third (GB) has a girl with her and a boy at home, and the fourth (GG) has a girl with her and a girl at home. A man walks up to one of the women at random and sees that there is a boy with her, and asks her how many children she has. She replies that she has 2 children. What is the probably that she has 2 boys?

Clearly, the probability is 1/2 or 50%.

Here is a long list of logic puzzles (no solutions posted yet). See how many you can figure out.

My wife and I are currently facilitators in Dave Ramsey's Financial Peace class and several people have asked me how I made my nice one page budget form. It is a Microsoft Excel file, and has everything squeezed in a very small space.

Here is a blank version of my Budget Template.
See also the bi-weekly budget form.

Update 11/15: I was asked for instructions on how to use this spreadsheet.

It is very much like the paper budget forms. Column B is the category, and column C is how much you have budgeted for that month. Column D is how much you have spent so far this month, so at the beginning of the month these will be all zero. Now column D is all formulas, since I didn't want to do math every time I wrote a check. So if you look at the second sheet "Actuals" you see a similar chart showing the same first 3 columns. Starting in column D, you can just enter one check per cell. So for example if you have spent $5, $20, and $15 on food, go to the food line and put 5 in column D, 20 in E and 15 in F etc. The total will automatically show up on the "Budget" sheet in column D.

Column E is simply a formula letting you know how much is left in that "envelope" for that category: i.e. Budgeted(C) - Actual(D).

The balances at the bottom are just for checking your math: Balance C should always be zero if your budget is balanced. Balance D should be exactly the same as the balance in your checkbook. Balance E should be the same as Balance D but reversed. If it is not, then there is a broken formula in the spreadsheet somewhere.

The tables on the right side:
The allocated savings register for you to record all of your savings goals, there is a formula for percent there but that is all.

The next table is the debt snowball table. The first column is the name of the debt, then the original amount, which is not really needed except that when you call in to scream "I'm debt free", Dave will ask you how much debt you paid off, and if you didn't write it down you won't know. The next column is how much the current principle balance on that debt is, and then you have a nice little percent.

The Upcoming table is a list of infrequent bills that I always forget about. I don't think that Dave has a form for this, but I needed it so that I remember to save up for big annual bills like car registration or quarterly insurance payments.

The next section in the black box, is what I call the motivating statement. It is what encourages me to keep going, when I can look at the budget taped to the side of the fridge and see in huge letters: "We saved $3,963 and paid off $16,883 in debt" it keeps me focused on the goal.

This article by Paul Graham is an excellent argument that the gap between the poor and the rich is not something to be feared, but rather a sign of a health country.

I have been using this online backup service at mozy.com. It actually works really well, doesn't get in the way, and you can restore files from the web.

If you use this link, then I get an extra 512MB quota also. (he he)

The system is free, and you start with 1GB. Paid subscriptions are available if you need more space. The client tool that does the backups is available for Windows only (as far as I know).