This is a guest post written by Paramdeep from Pristine. Chandoo.org is partnering with Pristine to bring an excel financial modeling online training program for you.
This is Part 1 of 6 on Financial Modeling using Excel
In this and next 5 posts, we are going to learn how to build a financial model to do project evaluation using Excel. The 6 parts of this tutorial are,
- Introduction to Financial Modeling
- Building a layout for Project Evaluation Model – Best practices
- Building Inputs and Assumptions Sheet
- Building Projections for Project Evaluation
- Modeling the Cash Flow Statement and Projections
- Putting it all together – Final Project Evaluation Model
- Join our Financial Modeling Classes
What is financial modeling?
Financial modeling is creating a complete program/ structure, which helps you in coming to a decision regarding investment in a project/ company. Now this could be on a simple piece of paper or in excel. The advantage with excel is that, even if you have calculation speed and accuracy like me (this is one place where I am like Einstien!), then also you would be able to come to the right conclusion!
Who does Financial Modeling?
Anybody dealing with any decision related to money (wish there was somebody who did not require that!). If you are involved in financial decision making/ planning related to large corporate, then you would definitely need financial modelling day in and day out. Financial modeling is a mandatory activity for investment bankers, bankers, project finance persons, equity research folks, PE & VCs.
What are the steps in building a financial model?
- Data collection – This is where the real front end banker works. She goes to the client, collects the data like revenue, growth, investments, need for money, etc.
- Back of the envelope calculations – Now most of the corporate guys are very hunky dory about their business. They usually think that their idea is one of a kind and is going to generate loads of mullah. Banker would sanitize their thoughts and try to figure out, if the business makes sense. Initially the thinking and analysis is very simple,
- Does the corporate guy look sober to me?
- How soon can I get my investment back?
- Is the revenue that he is projecting seem greater than the market size? 😉
You usually need no industry knowledge for this. Just keep your eyes and ears open and put your thinking cap on!
- Structured approach to thinking – Once the basic numbers seem reasonable (they make business sense and seem to be true as well), you have to dig deeper! This is where you need a complete financial model. And the first real step to doing that is to think of a structure of analysis. Thankfully finance has some basic theories in place and you can rely on them to proceed:
- Cash is the king – The more cash is generated (from the operations of the business) the better is the business
- Money today is better than money tomorrow – technically this can be called Time value of money. But it does not matter!
Practically these are the fundamental building blocks of analysis and you have to start thinking in these terms for the analysis
- Deciding on a Layout – Now when you start to put this plan in excel, the starting point is deciding on a layout for your financial model. Usually the following questions need to be answered:
- How much information/ data would your model have? If its going to be large, then it might make sense to break the model in multiple sheets
- What kind of assumptions would your model make? For better readability, we would try to keep assumptions in a different heading than the calculations and the final conclusion
- Different fonts/ formatting for assumptions and other parts might enhance readability as well
- Create logical modules for your model
- Keep your P&L, Balance Sheet, cash flow statement, etc. separate
- Even in P&L, keep the revenue generation separate from costs
One Advice for Aspiring Financial Modelers
Speed is the Key: Finally when you are dealing with tons of information, you can easily get bored. If you remember a bunch of keyboard shortcuts, then it would be very beneficial! Here are some resources to get you started:
- Comprehensive list of Excel Keyboard Shortcuts: Lists 97 shortcuts organized by functionality and usefulness.
- Favorite Shortcuts as voted by readers: Keyboard shortcuts shared by our readers.
- Using Mouse Effectively – Part 1 & Part 2: If you are going to use mouse, you better be productive at it.
An Example Financial Modeling Case
Now to make your life easy, we have done the first two parts for you! 🙂 There is a case (In the attached PDF file) that lists a situation and some of the data you might need to organize your thoughts. The decision is simple, would you advice Mr. Samar to invest in design Y?
Download the case pdf from here [pdf].
Once you have read the case and analyzed the numbers try creating a model for evaluation. Remember to make the layout of your model in such a way that navigation becomes easier.
What Next?
In the next installment of this tutorial, learn how to create a layout / template for our project evaluation model. We also discuss about some of the best practices to follow when building models in excel.
Join our Financial Modeling Classes
We are glad to inform that our new financial modeling & project finance modeling online class is ready for your consideration.
Please click here to learn more about the program & sign-up.
Share your Experience:
Do you build financial models? What is your experience like? What process do you follow and how do you plan the model? Do share your ideas and methods thru comments.
Added by Chandoo:
Thank you Paramdeep & Pristine:
Many thanks to Paramdeep and Pristine for making this happen. I am really enjoying this series and learning a lot of valuable tricks about financial modeling.
If you like this series, say thanks to Paramdeep. I am sure he can take any amount of appreciation without choking.
Join our Newsletter
if you are new here, consider joining my newsletter, because I can send you updates when new articles are posted (plus you get a cool e-book with 95 excel tips, free)
Pristine is an awesome training institute for CFA, PRIMA, GARP etc. They have trained folks at HSBC, BoA etc. Chandoo.org is partnering with Pristine to bring an excel financial modeling online training program for you.
20 Responses to “Simulating Dice throws – the correct way to do it in excel”
You have an interesting point, but the bell curve theory is nonsense. Certainly it is not what you would want, even if it were true.
Alpha Bravo - Although not a distribution curve in the strict sense, is does reflect the actual results of throwing two physical dice.
And reflects the following . .
There is 1 way of throwing a total of 2
There are 2 ways of throwing a total of 3
There are 3 ways of throwing a total of 4
There are 4 ways of throwing a total of 5
There are 5 ways of throwing a total of 6
There are 6 ways of throwing a total of 7
There are 5 ways of throwing a total of 8
There are 4 ways of throwing a total of 9
There are 3 ways of throwing a total of 10
There are 2 ways of throwing a total of 11
There is 1 way of throwing a total of 12
@alpha bravo ... welcome... 🙂
either your comment or your dice is loaded 😉
I am afraid the distribution shown in the right graph is what you get when you throw a pair of dice in real world. As Karl already explained, it is not random behavior you see when you try to combine 2 random events (individual dice throws), but more of order due to how things work.
@Karl, thanks 🙂
When simulating a coin toss, the ROUND function you used is appropriate. However, your die simulation formula should use INT instead of ROUND:
=INT(RAND()*6)+1
Otherwise, the rounding causes half of each number's predictions to be applied to the next higher number. Also, you'd get a count for 7, which isn't possible in a die.
To illustrate, I set up 1200 trials of each formula in a worksheet and counted the results. The image here shows the table and a histogram of results:
http://peltiertech.com/WordPress/wp-content/img200808/RandonDieTrials.png
@Jon: thanks for pointing this out. You are absolutely right. INT() is what I should I have used instead of ROUND() as it reduces the possibility of having either 1 or 6 by almost half that of having other numbers.
this is such a good thing to learn, helps me a lot in my future simulations.
Btw, the actual graphs I have shown were plotted based on randbetween() and not from rand()*6, so they still hold good.
Updating the post to include your comments as it helps everyone to know this.
By the way, the distribution is not a Gaussian distribution, as Karl points out. However, when you add the simulations of many dice together (i.e., ten throws), the overall results will approximate a Gaussian distribution. If my feeble memory serves me, this is the Central Limit Theorem.
@Jon, that is right, you have to nearly throw infinite number of dice and add their face counts to get a perfect bell curve or Gaussian distribution, but as the central limit theorem suggests, our curve should roughly look like a bell curve... 🙂
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I'm afraid to say that this is a badly stated and ambiguous post, which is likely to cause errors and misunderstanding.
Aside from the initial use of round() instead of int(),.. (you've since corrected), you made several crucial mistakes by not accurately and unambiguously stating the details.
Firstly, you said:
"this little function generates a random fraction between 0 and 1"
Correctly stated this should be:
"this little function generates a random fraction F where 0 <= F < 1".
Secondly, I guess because you were a little fuzzy about the exact range of values returned by rand(), you have then been just as ambiguous in stating:
"I usually write int(rand()*12)+1 if I need a random number between 0 to 12".
(that implies 13 integers, not 12)
Your formula, does not return 13 integers between 0 to 12.
It returns 12 integers between 1 and 12 (inclusive).
-- As rand() returns a random fraction F where 0 <= F < 1, you can obviously can only get integers between 1 and 12 (inclusive) from your formula as stated above, but clearly not zero.
If you had said either:
"I usually write int(rand()*12) if I need a random number between 0 to 11 (inclusive)",
or:
"I usually write int(rand()*12)+1 if I need a random number between 1 to 12 (inclusive)"
then you would have been correct.
Unfortunately, you FAIL! -- repeat 5th grade please!
Your Fifth Grade Maths Teacher
Idk if I'm on the right forum for this or how soon one can reply, but I'm working on a test using Excel and I have a table set up to get all my answers from BUT I need to generate 10,000 answers from this one table. Every time, I try to do this I get 10,000 duplicate answers. I know there has to be some simple command I have left out or not used at all, any help would be extremely helpful! (And I already have the dice figured out lol)
Roll 4Dice with 20Sides (4D20) if the total < 20 add the sum of a rerolled 2D20. What is the average total over 10,000 turns? (Short and sweet)
Like I said when I try to simulate 10,000turns I just get "67" 10,000times -_- help please! 😀
@Justin
This is a good example to use for basic simulation
have a look at the file I have posted at:
https://rapidshare.com/files/1257689536/4_Dice.xlsx
It uses a variable size dice which you set
Has 4 Dice
Throws them 10,000 times
If Total per roll < 20 uses the sum of 2 extra dice Adds up the scores Averages the results You can read more about how it was constructed by reading this post: http://chandoo.org/wp/2010/05/06/data-tables-monte-carlo-simulations-in-excel-a-comprehensive-guide/
Oh derp, i fell for this trap too, thinking i was makeing a good dice roll simulation.. instead of just got an average of everything 😛
Noteably This dice trow simulate page is kinda important, as most roleplay dice games were hard.. i mean, a crit failure or crit hit (rolling double 1's or double 6's) in a a game for example dungeons and dragons, if you dont do the roll each induvidual dice, then theres a higher chance of scoreing a crit hit or a crit failure on attacking..
I've been working on this for awhile. So here's a few issues I've come across and solved.
#1. round() does work, but you add 0.5 as the constant, not 1.
trunc() and int() give you the same distributions as round() when you use the constant 1, so among the three functions they are all equally fair as long as you remember what you're doing when you use one rather than the other. I've proven it with a rough mathematical proof -- I say rough only because I'm not a proper mathematician.
In short, depending on the function (s is the number of sides, and R stands in for RAND() ):
round(f), where f = sR + 0.5
trunc(f), where f = sR + 1
int(f), where f = sR + 1
will all give you the same distribution, meaning that between the three functions they are fair and none favors something more than the others. However...
#2. None of the above gets you around the uneven distribution of possible outcomes of primes not found in the factorization of the base being used (base-10, since we're using decimal; and the prime factorization of 10 is 2 and 5).
With a 10-sided die, where your equation would be
=ROUND(6*RAND()+0.5)
Your distribution of possible values is even across all ten possibilities.
However, if you use the most basic die, a 6-sided die, the distributions favor some rolls over others. Let's assume your random number can only generate down to the thousandths (0.000 ? R ? 0.999). The distribution of possible outcomes of your function are:
1: 167
2: 167
3: 166
4: 167
5: 167
6: 166
So 4 and 6 are always under-represented in the distribution by 1 less than their compatriots. This is true no matter how many decimals you allow, though the distribution gets closer and closer to equal the further towards infinite decimal places you go.
This carries over to all die whose numbers of sides do not factor down to a prime factorization of some exponential values of 2 and 5.
So, then, how can we fix this one, tiny issue in a practical manner that doesn't make our heads hurt or put unnecessary strain on the computer?
Real quick addendum to the above:
Obviously when I put the equation after the example of the 10-sided die, I meant to put a 10*RAND() instead of a 6*RAND(). Oops!
Also, where I have 0.000 ? R ? 0.999, the ?'s are supposed to be less-than-or-equal-to signs but the comments didn't like that. Oh well.
How do you keep adding up the total? I would like to have a cell which keeps adding up the total sum of the two dices, even after a new number is generated in the cells when you refresh or generate new numbers.
So, how do you simulate rolling 12 dice? Do you write int(rand()*6) 12 times?
Is there a simpler way of simulating n dice in Excel?
I've run this code in VBA
Sub generate()
Application.ScreenUpdating = False
Application.Calculation = False
Dim app, i As Long
Set app = Application.WorksheetFunction
For i = 3 To 10002
Cells(i, 3).Value = i - 2
Cells(i, 4).Value = app.RandBetween(2, 12)
Cells(i, 5).Value = app.RandBetween(1, 6) + app.RandBetween(1, 6)
Next
Application.ScreenUpdating = True
Application.Calculation = True
End Sub
But I get the same distribution for both columns 4 and 5
Why ?
@Mohammed
I would expect to get the same distribution as you have effectively used the same function