# Crystal Ball User Manual Pdf When the values of two variables depend upon one another in whole or in part, the variables are considered correlated. If you like, you can use the mouse to individually alter the probabilities and shapes of the data points and ranges so that they more accurately reflect the uncertain variable. Note that in this example the dealership has made several simplifying assumptions about the conditions. The first row in the cell range should contain the minimum value of the data and should have a cumulative probability of zero. ## About the Crystal Ball Documentation Set

It can also be used to describe chemical reactions and the course of growth for a population or individual. Sometimes you have to press two or more keys simultaneously. It is the same with the variables that have a known range of values but an uncertain value for any particular time or event e. For a complete discussion of probability distributions, refer to the sources listed in the bibliography. Decision-makers can use the normal distribution to describe uncertain variables such as the inflation rate or the future price of gasoline.

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When an increase in one variable is associated with a decrease in another variable, the correlation is called negative or inverse and. If alpha is less than beta, the distribution is said to be positively skewed most of the values are near the minimum value. Select a cell or a range of cells.

The distribution with the highest ranking fit is chosen to represent your data. If you are experienced in statistical methods, you probably will have a feel for which distribution to use. You can use the Data button to pull numbers from specified cell ranges on the worksheet rather than typing them in the Custom Distribution dialog. Due to round-off differences between various system configurations, you might obtain slightly different calculated results than those shown in the examples. Second, you organize the data into a meaningful format and plot the data as a frequency distribution on a chart. The assumption cell is now green.

The Oracle Crystal Ball User's Guide is intended for students, analysts, engineers, executives, and others who want to learn how to use the main features of Crystal Ball. If you are a new user, you should read the sections in order. Because the beta distribution is very complex, the methods for determining the parameters of the distribution are beyond the scope of this manual. From there, this manual guides you step by step, explaining Crystal Ball terms, procedures, and results.

You can change the probability of a discrete range by dragging the value bar as you did for the continuous range. Each Classical Theory The likelihood of an event bar on the chart represents the likelihood, or probability, of occurring. These conditions match those of the beta distribution.

## Crystal Ball User Manual

The tools from the next four groups are from the Run menu. Defining Other Model Elements Describes how to define decision variable cells and forecast cells in models.

Forecast Statistics window terms These terms are listed in the Forecast Statistics window when you run a simulation in Crystal Ball and in the reports you can create for each forecast. Technical support Decisioneering, Inc. When values are widely scattered about the mean, the variance is larger.

The Correlated Assumptions feature in Crystal Ball lets you use correlation coefficients to define the dependencies between assumptions. Determining profit Now you can use Crystal Ball to determine the statistical likelihood of making a profit and what is the most likely range. Report location This option lets you create a Crystal Ball report in a new worksheet of an existing workbook or in a new workbook as before. Crystal Ball is a user-friendly, basic electronics fundamentals pdf graphically oriented forecasting and risk analysis program that takes the uncertainty out of decision-making.

Click any value bar to display its corresponding data boxes. In reality, the total number of computer purchasers is finite, and some might have influenced the purchasing decisions of others. To select a parameter set to use as the default when defining new assumptions of this type, select Set Default from the popup menu. So, calculating the range requires you to replace the uncertain value several times to see what effect the minimum, most likely, and maximum values have. Now specify the parameters for the triangular distribution. Caveat Each adjustment changes the characteristics of the probability distribution. You would enter these values as the parameters of the uniform distribution in Crystal Ball. Even then, you would likely be left with a mountain of data instead of the overall profit and loss picture.

The decision variable cells must contain simple numeric values, not formulas or text. The geometric distribution represents the number of trials until the next success while the binomial represents the number of successes in a fixed number of trials. After you select the mean parameter, you can estimate the scale parameter. In this example, you are a potential purchaser of the Futura Apartments complex.

The example below shows three correlation coefficients. For each value, calculate the difference between the value and the mean. Take a look at the Vision Research workbook.

The Run Preferences Trials dialog appears. In the dialog, type a name for the assumption optional. For each selected cell or cells in the selected range, Crystal Ball displays the Distribution Gallery. Beta distribution The beta distribution is a very flexible distribution commonly used to represent variability over a fixed range.

Glossary Defines terms specific to Crystal Ball and other statistical terms used in this manual. This tutorial explains the reasons for choosing a particular distribution for each assumption. Each goodness-of-fit test is calculated for every distribution, but only the selected test determines how the distributions are ranked. This section uses real-world examples to describe the custom distribution. If desired, you can override the highest-ranking probability distribution with another one of your choice.  