If you ever had to simulate random outcomes in excel sheet, you might have already heard of about the spreadsheet function rand(), this little function generates a random fraction between 0 and 1 whenever you use it. So I usually write = if I need a random number between 0 to 12. Of course, if you have analysis tool pack installed like I do, then we can use round(rand()*12,0)int(rand()*12)+1randbetween(0,12) to do the same.
In order to simulate a dice throw, thus you can use round(rand()*5,0)int(rand()*6)+1
So, what would you do if you need to simulate the face total when you throw 2 dice?
round(rand()*10,0)int(rand()*11)+2
Wrong
Why? Apparently a random number between 2 and 12 (1 is not possible as the minimum you can get when you throw two dice is 2) doesn’t simulate 2 dice throws properly.
The CORRECT way to do this is instead generate 2 individual random numbers and add them up, like:
round(rand()*5,0)int(rand()*6) + 1 + round(rand()*5,0)int(rand()*6) + 1
Here is why this is correct way to simulate dice throws using random number generator functions:
I have ran these 2 random functions each for 2500 times and plotted the distribution:
As you can see, the left plot of int(rand()*11)+2 tells that each of the 11 possibilities (2,3,4,5,6,7,8,9,10,11) are equally likely. But that is not what happens when you throw a dice, you see an awful lot more 5,6,7,8 than you see a perfect 12 or 2. And there is a reason for that, the distribution of 2 dice throws is actually a bell curve, and when you use int(rand()*6) + int(rand()*6) + 2 the distribution is bell curvish.
Update: Thanks to Jon for pointing out that round() is not the choice if you want random integers, you should use int instead. See his explanation in the comments and the illustration here.
I have used this logic to simulate monopoly board game and prove that it is not really that random.
More on games: Bingo / Housie ticket generator excel sheet
6 Responses to “A quick personal update”
Thank you for the personal update. It was quite encouraging and a breath of fresh air in my Inbox. Take care and stay safe.
David
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Virus obstructs lungs with thick mucus that solidifies.
Consume lot hot liquids like tea, soup, and sip of hot liquid every 20 min
Gargle w antiseptic of lemon, vinegar, & hot water daily
It attaches to hair/clothes detergent kills it, when come from st go straight shower
Hang dirty clothes in sunlight/cold overnight or wash immediately.
Wash metal surfaces as it can live on them 9 days
Do not touch hand rails
Do not smoke
Wash hands foaming 20 sec every 20 min
Eat fruit/veg and up zinc levels.
Animals do not spread it
Avoid common flu
Avoid eat/drink cold things
If feel sore throat do above immediate as virus is there 3-4 days before descends into lungs
Would love help with my database mgt in excel.
Thanks for being thoughtful of us.
BTW How do you track your expenses/income in excel? Can you share the worksheet please.
Stay safe you and your family, best wishes.
Thanks for the update and happy to know that you and family are doing good. A 21 day lockdown has now been announced in India (I live around Kolkata) so it's uncertain times ahead. I check up on your wonderful articles often and will do so even more regularly now. Stay safe and God bless.
Hi from Argentina, I follow you for a lot of years now. We here are in a quarantine for 2 or 3 weeks, because the pandemia.
Excel is also my passion and I came here looking for a Num2Words formula, but in spanish. If anyone have it, please let me know.
Best regards.
Pablo Molina
La Rioja - Argentina
I'm glad to have your personal update. I'm from India & following you for so many years. Cheers to have any further personal update.