Frequently Asked Questions

Click the headings in the bar above to jump to questions relating to Monte Carlo simulations, distributions, questions about our Debug Model tool, or general and troubleshooting-related questions.

Simulation Information

Educational information on Monte Carlo simulations and questions relating the Monte Carnival simulation tool

What is a Monte Carlo Simulation?

A Monte Carlo simulation is a computerized mathematical technique that is used to assist in the decision making process. A Monte Carlo simulation simulates a model or a process using a number of trials, records a variable during each trial run, and takes the average of that variable. More meticulous programs perform statistical calculations on the result, such as finding the skewness and kurtosis, and make a histogram or percentile graph using the list of variables from each trial. The average from the trials is interpreted as the forecast of what the variable will be in the future according to the model or process being simulated.


How are Monte Carlo Simulations Used?

Monte Carlo simulations are used in fields including Physics, Finance, Economics, Design, Management, Meteorology, Biology, Psychology, Geology, Marketing, Engineering, Data Analysis, Healthcare, Energy, Agriculture, and more. For example, a meteorologist will run a Monte Carlo simulation on their hurricane model to predict the expected path a hurricane will take. The model will give the meteorologist a rough idea of how the situation may play out, allowing them to make a wide range of predictions for where the hurricane will make landfall. The model is not a perfect forecast of the future, it only predicts a range or area that the hurricane likely will land, but this approximate knowledge can be extremely helpful when making evacuation plans. Monte Carlo simulations may not be able to tell the future, but they certainly can help us make decisions by giving us a slight probabilistic edge to make decisions with.


Is there a limit to the number of iterations I can run in a Monte Carnival simulation?

No, there is no limit. However, as you increase the number of trials it will take longer and longer to run a simulation.


What is a Forecast Value cell?

The Forecast Value cell is the cell that contains the variable that you want to simulate and is influenced by random variables in your process or model.


How many forecast cells can I simulate in a Monte Carnival simulation?

You can only run a Monte Carnival simulation on 1 forecast cell. If you select a range of cells when choosing a forecast variable, Monte Carnival will select the top-left most cell out of the group of cells you selected.


How many decimal places are shown in the Monte Carnival output page?

For the statistical portion of the output page, Monte Carnival does not put a limit on the number of decimal places and uses the default number of decimals in Excel, which shows up to 15 decimal places. For the Histogram chart labels, the maximum decimal places shown in Monte Carnival is 5, which happens when the mean is less than 1. For aesthetic purposes, in situations where the mean is greater than 1, Monte Carnival chooses the number of decimal places depending on the size of the mean value.


How many labels are shown in the Monte Carnival Histogram?

There are 20 labels. This is always the case, which means the Histogram may look a bit odd if there are less than 20 different values in the forecast value list or if there are less than 20 iterations.


Can I run a Monte Carnival simulation on any alpha-numeric value?

No. You can only run a Monte Carnival simulation on a numeric value. If an error message appears or there is a null value in the forecast cell, Monte Carnival will stop the simulation and tell you to fix the problem before running another simulation.


When I check the "Generate List of Forecast Values" box, what is the maximum amount of values the list can generate?

The "Generate List of Forecast Values" option will generate up to 262,000 values in the list in the default table format. If you entered a number of iterations higher than 262,000, the list will fill up 262,000 values in the table and then continue to add trials 262001... and so on under the first column. The only limit on the number of iterations is the Excel limit, but Monte Carnival has been tested using up to 1,000,000 iterations with no problems. Beyond that, Monte Carnival will stop recording values at Excel's row limit.





Distribution Information

Educational information and questions about the 12 random distribution functions included in Monte Carnival

What distributions are included in Monte Carnival?

Monte Carnival has 12 different distributions to choose from including Normal, Lognormal, Triangular, Uniform, Discrete (With up to 10 values and probabilities), Yes/No, Gamma, Beta, T, F, Chi-Squared, and Binomial.


Do the distribution formulas update with a refresh or re-calculation of a cell or workbook?

Yes! If you want the random numbers generated by the formula to stay the way they are, simply copy and paste the values in the cell to lock them.


Can I enter the functions in a cell rather than use the Insert a Distribution button?

Yes. The functions can be found in the questions below.


What is a Normal distribution?

A Normal distribution is a bell-shaped distribution, known as the "Bell Curve," that makes frequent appearances in many real world situations. For example, population heights follow a normal distribution with adult male heights averaging 70 inches with a standard deviation of 4 inches. This means that roughly 68% of the population of adult males will have a height between 66 and 74 inches, 95% of the population of adult males will be between 62 and 78 inches tall, and 99.7% of the population of adult males will be between 58 and 82 inches tall.


What is the Normal Distribution Function in Monte Carnival?

The formula is =MCNormalDist(Mean, Standard Deviation). The mean can be any number and the standard devation must not be zero or negative. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Lognormal distribution?

A Lognormal distribution is a probabilistic distribution whose logarithm follows a normal distribution. Lognormal distributions are used to model things such as rainfall amounts, the volume of gas in a reserve of petroleum, and the quantity of milk produced by cows.


What is the Lognormal Distribution Function in Monte Carnival?

The formula is =MCLognormalDist(Mean, Standard Deviation). The mean can be any number and the standard devation must not be zero or negative. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Triangular distribution?

A Triangular distribution is a probability distribution that is shaped like a triangle when graphed. This is due to having a minimum, maximum, and a most likely value as inputs. This distribution is convenient when there needs to be an upper and lower limit on a variable.


What is the Triangular Distribution Function in Monte Carnival?

The formula is =MCTriangleDist(Minimum, Most Likely, Maximum). The minimum cannot be greater than the maximum and the most likely cannot be greater than the maximum or less than the minimum. Values can be positive or negative. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Uniform Distribution?

A Uniform distribution is a rectangle-shaped distribution that generates a random value between a minimum and a maximum value with equal probability of being chosen. This distribution is useful when all values between the minimum and maximum are equally likely of being chosen.


What is the Uniform Distribution Function in Monte Carnival?

The formula is =MCUniformDist(Minimum, Maximum). The minimum cannot be greater than the maximum. The minimum and maximum values can be positive or negative. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Discrete distribution?

A Discrete distribution is useful when each outcome value has a probabilty of being chosen. For example, a coin flip follows a discrete distribution. The probability of landing on heads is 50% and the problem of landing on tails is also 50%.


What is the Discrete Distribution Function in Monte Carnival?

The formula is =MCDiscreteDist(Value 1, Probability 1, Value 2, Probability 2, Value 3, Probability 3.......Value 10, Probability 10). Values can be any alpha-numeric character. The sum of the probabilities entered must add up to 1. There must be a minimum of two values and two probabilities entered. You can enter up to 10 values that are associated with probabilities with the Monte Carnival Discrete distribution function. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Yes/No distribution?

A Yes/No distribution by default gives a 50% probability to both inputs, so that each value will appear 50% of the time.


What is the Yes/No Distribution Function in Monte Carnival?

The formula is =MCYesNoDist(Value if Yes, Value if No). Values can be any alpha-numeric character. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Gamma distribution?

A Gamma distribution is a two-parameter distribution that is used widely in engineering, business, and science for models that have skewed distributions.


What is the Gamma Distribution Function in Monte Carnival?

The formula is =MCGammaDist(Alpha, Beta). Alpha and beta values must be non-zero and non-negative. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Beta Distribution?

A Beta distribution is a statistical distribution that requires two parameters, alpha and beta, and represents a distribution of probabilities. For example, batting averages can be modeled using Beta distributions.


What is the Beta Distribution Function in Monte Carnival?

The formula is =MCBetaDist(Alpha, Beta, Minimum (Optional), Maximum (Optional)). Alpha and beta values must be non-zero and non-negative. The minimum cannot be greater than the maximum, but both the minimum and maximum values are optional. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a T Distribution?

A T distribution is a probability distribution that is used to predict population parameters given that a sample size is small or if the population variance is not known.


What is the T Distribution Function in Monte Carnival?

The formula is =MCTDist(Degrees of Freedom). The degrees of freedom value must be equal to or greater than 1. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is an F distribution?

An F distribution is a right-skewed probabilty distribution that requires two degree of freedom values. The F distribution is commonly used for hypothesis testing the equality of two population variances.


What is the F Distribution Function in Monte Carnival?

The formula is =MCFDist(Degree of Freedom 1, Degree of Freedom 2). The degree of freedom values must be equal to or greater than 1. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Chi-Squared distribution?

A Chi-Squared distribution that has x degrees of freedom is the distribution of a sum of the squares of x independent standard normal random variables.


What is the Chi-Squared Distribution Function in Monte Carnival?

The formula is =MCChiSquaredDist(Degrees of Freedom). The degrees of freedom value must be a number greater than 0. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


What is a Binomial distribution?

A Binomial distribution, a type of Bernoulli distribution, is a statistical distribution that is based on a probability and a number of trials.


What is the Binomial Distribution Function in Monte Carnival?

The formula is =MCBinomDist(Number of Trials, Alpha). The number of trials value must be a number greater than zero and the alpha value must be between zero and one. You can either enter the formula in a cell or use the Insert a Distribution button to insert the formula into a cell or a range of cells.


Can I only insert a distribution one cell at a time?

No. You can choose to insert a distribution in one or more cells at a time. To choose a box or an adjacent range, simply choose a box in Excel that you want to enter the formulas into. To insert a distribution into cells that are not adjacent, hold down CTL as you select the cells.




The Debug Model Tool

Information on our Debug Model tool

What is the Debug Model tool?

The Debug Model tool is a tool that is useful when your model is generating a value that it should not, and you want to find out why. The tool allows you to say, "If this cell goes above 5,000 stop the simulation and let me see the instance in the model that is actually calculating that number. This will allow you to save a lot of time instead of manually re-calculating a workbook (or multiple workbooks) until you arrive at the mistaken value. You can run the Debug Model tool on any cell or a group of cells all at once, not just the forecast cell.


How does the Debug Model tool work?

To use the Debug Model tool click the "Debug Model" button in the ribbon tab and the Debug Model window will appear. Select a cell or a range of cells that you want to check on, select a conditional statement from the drop-down box that you want to use to test the cell or group of cells with, and enter a value that you want to test the cell or group of cells against. For example, I select the cell with the formula =Randbetween(1, 10000), I choose the conditional statement "Equal to", I enter the value 9999, and then I click start. Monte Carnival will re-calculate the worksheet that contains the test cell (or all open workbooks if you check the checkbox) until the test cell hits 9999. When the condition of being equal to 9999 is met, the simulation stops, leaving the 9999 value and the calculations behind it intact. I can now look over the calculations in the model that cause the test cell to equal 9999.


If the condition I specified is never met, will the Debug Model tool run forever?

No, the limit on the Debug Model tool is 100,000 iterations. If your condition is still not met after 100,000 iterations, you will receive a message and be told to check to see if your condition is feasible and will then be re-directed back to the "Debug Model" window.


What conditions can I select when using the Debug Model tool?

You can choose the conditional statements Greater Than, Greater Than or Equal to, Equal to, Not Equal to, Less Than, and Less Than or Equal to.



General, Tips, and Troubleshooting

General questions about Monte Carnival, tips, and troubleshooting methods

How do I stop Monte Carnival or the Debug Model tool once it is running?

There are three ways to do this. The first is to hit the "Cancel" button on the window. The second and third ways are to press the ESC key or press CTL + break.


If my model is in multiple worksheets or workbooks, do Monte Carnival and the Debug Model tool still work?

Yes! In both the Monte Carnival simulation window and the Debug Model window is a checkbox labeled, "Calculate all Open Workbooks." If this is not checked, Monte Carnival will only calcluate the sheet that contains the forecast value cell/test cell. All linking workbooks or worksheets that contain relevant calculations must be open for this option to work.


I deleted the Monte Carnival ribbon tab and then re-added it, but all of the buttons are gone, What should I do?

When you install the Monte Carnival Add-In, the ribbon is installed automatically upon opening the add-in. If you deleted the Monte Carnival tab using the "Customize Ribbon" option in Excel and then added it back, the Monte Carnival custom tab will be blank. To fix this, uninstall the add-in from Excel by going to File > Options > Add-Ins > Excel Add-Ins in the drop-down box > Uncheck the Monte Carnival Add-In box. Then re-install the Add-In by using the same path specified above and checking the Monte Carnival Add-In. You can also do this from the Developer ribbon tab by clicking Excel Add-Ins and checking/unchecking the Monte Carnival checkbox there.


I uninstalled the Monte Carnival ribbon Add-In but the ribbon tab is still there, how do I make it go away?

To hide the Monte Carnival ribbon tab, go to File > Options > Customize Ribbon > Uncheck the custom Monte Carnival tab. However, if you do want to re-install Monte Carnival you must re-check the tab and then uninstall and re-install the Monte Carnival Add-In. For directions on how to do this, see above question.


I am having trouble with the Monte Carnival ribbon tab, what else could be the problem?

There may be other add-ins running on your machine that are causing trouble with the installation of the Monte Carnival ribbon tab. Try uninstalling other Excel add-ins that you have running and then re-install the Monte Carnival Excel Add-In. For directions on how to do this, see above questions.


Does Monte Carnival require macros to be enabled in Excel?

Monte Carnival requires all macros to be enabled. You may need to update your macro settings in the Trust Center menu. To do this, go to File > Options > Trust Center > Trust Center Setting > Macro Settings > Make sure the checkbox labeled "Disable all Macros with notification" or “Enable all Macros” is selected. If this doesn't work, check the “Trust Access to the VBA Project Model” box. You may also need to click the Enable Macros message button upon opening a workbook if you are given the option to.


The Histogram labels do no conform to what I want to show, changing the effectiveness of the Histogram. Can I make my own Histogram with Monte Carnival data?

Yes! While there is no wizard to make a histogram chart within Monte Carnival, you are able to select the "Generate a List of Forecast Values" checkbox and can then create a Histogram using that data. This may be a bit more labor intensive, but nonetheless you have the optionality to do so if you wish.


Why is Monte Carnival or the Debug Model tool taking so long to run?

If you selected the "Generate a List of Forecast Values" checkbox or the "Calculate All Open Workbooks" checkbox, then both tools will run a bit slower than when these checkboxes were unchecked. When these checkboxes are checked, Monte Carnival has more steps to perform on the calculation of one iteration, and this effect will compound as the number of trials increases. As a general rule, the higher the number of iterations, the longer it will take to run a simulation.


Does Monte Carnival work with Excel on Macs?

Not currently. There may be plans in the future to expand Monte Carnival to work with Macbook devices, but as of now it only works on PCs.


Is Monte Carnival compatible with Windows 32-bit and Windows 64-bit machines?

Yes!


Is Monte Carnival compatible with Excel 1997, 2000, 2003, 2007, 2010, 2013, and 2016?

Yes!


I am receiving an error message from my browser saying that the Monte Carnival Trial download installation file or the Monte Carnival full version installation file may be unsafe, is it safe to download these files on my computer?

Yes! Your browser or system may be flagging the files as potentially dangerous but both files are completely safe and will not harm your computer in any way whatsoever.


I did not receive an email receipt after purchasing Monte Carnival, what can I do?

The email may have been sent to your spam inbox. Check spam and see if the email is there. If it is not, please go to our contact page and send us an email that includes the email that was used to purchase Monte Carnival. We will try and resolve your issue as soon as possible.


My question was not answered in the FAQ section, what can I do?

We have a contact page at the bottom of our home page that allows you to send us an email detailing your problem. To get there from here, click the Contact tab at the top or the bottom of the page, and you will be re-directed you to our Contact section. Before you send the email, make sure your email address is valid. If it is not, we will not receive your email and will not be able to help you with your question.