Crystal Ball实验操作过程
神奇的水晶结晶实验
神奇的水晶结晶实验
水晶结晶实验是一种既有趣又神奇的实验，通过简单的材料和操作，就能观察到水晶在慢慢生长的过程中产生美丽的结晶。
本文将介绍如
何进行水晶结晶实验，并解释实验背后的科学原理。
首先，准备实验所需的材料。
你需要烧杯、布棉线、饱和的硼酸溶液、清洁透明的玻璃瓶、食盐和糖。
将烧杯放在温水中，加热直到水
温达到80°C。
然后将饱和的硼酸溶液倒入玻璃瓶中，加入少量的食盐
和糖，用布棉线悬挂在溶液中央，让线头轻轻接触底部。
接着，将瓶子放在室温下静置。
随着时间的推移，你将会看到水晶
开始在棉线上生长。
这种美丽的结晶是由于溶液中过饱和度过高，导
致结晶物质沉积在布棉线上形成晶体。
有趣的是，你可以根据自己的
喜好在实验过程中添加不同颜色的食用色素或荧光粉，让水晶结晶呈
现出绚丽多彩的效果。
此外，水晶结晶实验还能帮助我们理解一些化学原理。
在实验中，
我们可以观察到溶液中溶质随着温度的变化而溶解度发生变化，从而
影响到结晶的生长速度和形态。
此外，通过实验我们也可以了解到过
饱和度对结晶生长的影响，以及晶体的形成过程。
总的来说，水晶结晶实验是一种简单而有趣的科学实验，既可以锻
炼我们的动手能力，又能增进对化学原理的理解。
希望通过这篇文章
的介绍，能让更多的人对水晶结晶实验产生兴趣，并亲自动手尝试这
个神奇的实验。
风险管理软件CrystalBall使用指导
风险管理软件C r y s t a l B a l l使用指导 Ting Bao was revised on January 6, 20021Monte-Carlo Simulation with Crystal BallTo run a simulation using Crystal Ball:1. Setup SpreadsheetBuild a spreadsheet that will calculate the performance measure ., profit) in terms of the inputs (random or not). For random inputs, just enter any number.2. Define Assumptions—., random variablesDefine which cells are random, and what distribution they should follow.3. Define Forecast—., output or performance measureDefine which cell(s) you are interested in forecasting (typically the performance measure, ., profit).4. Choose Number of TrialsSelect the number of trials. If you would later like to generate the Sensitivity Analysis chart, choose “Sensitivity Analysis” under Options in Run Preferences.5. Run SimulationRun the simulation. If you would like to change parameters and re-run the simulation, you should “reset” the simulation (click on the “Reset Simulation” button on the toolbar or in the Run menu) first.6. View ResultsThe forecast window showing the results of the simulation appears automatically after (or during) the simulation. Many different results are available (frequency chart, cumulative chart, statistics, percentiles, sensitivity analysis, and trend chart). The results can be copied into the worksheet.Crystal Ball Toolbar:Define Define Run Start Reset Forecast Trend Assumptions Forecast Preferences Simulation Simulation Window ChartWalton Bookstore Simulation with Crystal BallRecall the Walton Bookstore example: It is August, and they must decide how many of next year’s nature calendars to order. Each calendar costs the bookstore $ and is sold for $10. After February, all unsold calendars are returned to the publisher for a refund of $ per calendar. Suppose Walton predicts demand will be somewhere between 100 and 300 (discrete uniform).Demand = d ~ Uniform[100, 300]Order Quantity = Q (decision variable)Revenue = $10 * Min(Q, d)Cost = $ * QRefund = $ * Max(Q–d, 0)Profit = Revenue – Cost + RefundStep #1 (Setup Spreadsheet)Walton Bookstore Simulation with Crystal BallStep #2 (Define Assumptions —., random variables)— color code (blue):and click on the “Define Assumptions” button in toolbar (or in the Cell menu):Select type of distribution:Provide parameters of distributions:Walton Bookstore Simulation with Crystal BallStep #3 (Define Forecast—., output)click on the “Define Forecast” button in toolbar (or in the Cell menu),and fill in the Define Forecast dialogue box.Step #4 (Choose Number of Trials)Click on the “Run Preferences” button in toolbar (or in the Run menu):and select the number of trials to run.Walton Bookstore Simulation with Crystal BallStep #5 (Run Simulation)Click on the “Start Simulation” button in toolbar (or Run in the Run menu):Step #6 (View Results)The results of the simulation can be viewed in a variety of different ways (frequency chart, cumulative chart, statistics, and percentiles). Choosedifferent options under the View menu in the forecast window.The results can be copied into a worksheet or Word document (choose Copy under the Edit menu in the simulation output window.Using Trend Charts to Find the Impact of Order Quantity on Potential ProfitDefine several forecast cells (G14:G18) for several possible order quantities (Q=100, 150, 200, 250, 300). Use the same random order quantity for each to compare them more equally ., one assumption cell for demand—C14—with the rest set equal to C14).After running the simulation, choose “Open Trend Chart” in the Run menu.This chart gives “certainty bands” for the forecast cells. 10% of the time, the project duration will fall within the inner band (light blue), 25% of the time within the 2nd band (red), 50% of the time within the third band (green), and 90% of the time within the outside band (dark blue).Project Management—Global OilGlobal Oil is planning to move their credit card operation to Des Moines, Iowa from their home office in Dallas. The move involves many different divisions within the company. Real estate must select one of three available office sites. Personnel has to determine which employees from Dallas will move, how many new employees to hire, and who will train them. The systems group and treasurer’s office must organize the new operating procedure and make financial arrangements. The architects will have to design the interior space, and oversee needed structural improvements. Each site is an existing building with sufficient open space, but office partitions, computer facilities, furnishings, and so on, must all be provided.A complicating factor is that there is an interdependence of activities. In other words, some parts of the project cannot be started until other parts are completed. For example, Global cannot construct the interior of an office before it has been designed. Neither can it hire new employees until it has determined its personnel requirements.The necessary activities and their necessary predecessors (due to interdependence) are listed below. Three estimates are made for the completion time of each activity—the minimum time, most likely time, and maximum time.Start EndGlobal Oil Simulation with Crystal BallStep #1 (Setup Spreadsheet)Step #2 (Define Assumptions—., random variables)Each of the random activity times (B, C, D, E, G, and I) is assumed to follow the triangular distribution.Global Oil Simulation with Crystal BallStep #3 (Define Forecast—., output)Cell J15 is the forecast cell:Step #4 (Choose Number of Trials)500 trials were run. In addition, Sensitivity Analysis was enabled in the Options of the Run Preferences dialogue box. This allows for the generation of sensitivity analysis results later.Step #5 (Run Simulation)Step #6 (View Results)Additional Results Available with Crystal BallSlide the triangles below the histograms to determine the probability that the output (project duration) is less than a certain value ., a deadline), greater than a certain value, or between any two values (by sliding both triangles).Alternatively, you can type in values for the lower bound or upper bound to determine the probability. You can also type in a probability (in “Certainty”), and it will determine the range that has that probability.There is a 79% chance the project will be completed within 150 days.There is a % chance that the project will take more than 160 days.Sensitivity ChartChoose “Open Sensitivity Chart” in the Run menu. Note that this chart isonly available if you selected the “Sensitivity Analysis” option under Run Preferences. This chart gives an indication as to which random variables(activity times) have the greatest impact on the output cell (projectcompletion time).followed by activity D, C, I, and B. Variability in activity G has almost no impact.Fitting a DistributionCrystal Ball can be used to “fit” a distribution to data.The following data has been collected for the previous 100 phone calls to a mail-order house:(80 rows have been hidden)Fitting Data to a DistributionUsing Crystal Ball to fit data to a distribution1. Select a spreadsheet cell.2. Choose Define Assumption.3. Click the Fit button, then select the source of the fitted data.4. Click the Next button, then select the distributions to try tofit.5. Click OK.Interarrival TimeService Time。
风险管理软件crystalball使用指导
Monte-Carlo Simulation with Crystal Ball®To run a simulation using Crystal Ball®:1. Setup SpreadsheetBuild a spreadsheet that will calculate the performance measure ., profit) in terms of the inputs (random or not). For random inputs, just enter any number.2. Define Assumptions—., random variablesDefine which cells are random, and what distribution they should follow.3. Define Forecast—., output or performance measureDefine which cell(s) you are interested in forecasting (typically the performance measure, ., profit).4. Choose Number of TrialsSelect the number of trials. If you would later like to generatethe Sensitivity Analysis chart, choose “Sensitivity Analysis” under Options in Run Preferences.5. Run SimulationRun the simulation. If you would like to change parameters and re-run the simulation, you should “reset” the simulation (click on the “Reset Simulation” button on the toolbar or in the Run menu) first.6. View ResultsThe forecast window showing the results of the simulation appears automatically after (or during) the simulation. Many different results are available (frequency chart, cumulative chart, statistics, percentiles, sensitivity analysis, and trend chart). The results can be copied into the worksheet.Crystal Ball Toolbar:Define Define Run Start Reset Forecast TrendAssumptions Forecast Preferences Simulation Simulation Window ChartWalton Bookstore Simulation with Crystal Ball®Recall the Walton Bookstore example: It is August, and they must decide how many of next year’s nature calendars to order. Each calendar costs the bookstore $ and is sold for $10. After February, all unsold calendars are returned to the publisher for a refund of $ per calendar. Suppose Walton predicts demand will be somewhere between 100 and 300 (discrete uniform).Demand = d ~ Uniform[100, 300]Order Quantity = Q (decision variable)Revenue = $10 * Min(Q, d)Cost = $ * QRefund = $ * Max(Q–d, 0)Profit = Revenue – Cost + RefundStep #1 (Setup Spreadsheet)Walton Bookstore Simulation with Crystal Ball ® Step #2 (Define Assumptions —., random variables)Select the cell that contains the random variable (B17) — color code (blue):and click on the “Define Assumptions” button in toolbar (or in the Cell menu):Select type of distribution:Provide parameters of distributions:Walton Bookstore Simulation with Crystal Ball®Step #3 (Define Forecast—., output)Select the cell that contains the output variable to forecast (F17):click on the “Define Forecast” but ton in toolbar (or in the Cell menu),and fill in the Define Forecast dialogue box.Step #4 (Choose Number of Trials)Click on the “Run Preferences” button in toolbar (or in the Run menu):and select the number of trials to run.Walton Bookstore Simulation with Crystal Ball®Step #5 (Run Simulation)Click on the “Start Simulation” button in toolbar (or Run in the Run menu):Step #6 (View Results)The results of the simulation can be viewed in a variety of different ways (frequency chart, cumulative chart, statistics, and percentiles). Choose different options under the View menu in the forecast window.The results can be copied into a worksheet or Word document (choose Copy under the Edit menu in the simulation output window.Using Trend Charts to Find the Impact of Order Quantity on Potential ProfitDefine several forecast cells (G14:G18) for several possible order quantities (Q=100, 150, 200, 250, 300). Use the same random order quantity for each to compare them more equally ., one assumption cell for demand—C14—with the rest set equal to C14).After running the simulation, choose “Open Trend Chart” in the Run menu. This chart gives “certainty bands” for the forecast cells. 10% of the time, the project duration will fall within the inner band (light blue), 25% of the time within the 2nd band (red), 50% of the time within the third band (green), and 90% of the time within the outside band (dark blue).Project Management—Global OilGlobal Oil is planning to move their credit card operation to Des Moines, Iowa from their home office in Dallas. The move involves many different divisions within the company. Real estate must select one of three available office sites. Personnel has to determine which employees from Dallas will move, how many new employees to hire, and who will train them. The systems group and treasurer’s office must organize the new operating procedure and make financial arrangements. The architects will have to design the interior space, and oversee needed structural improvements. Each site is an existing building with sufficient open space, but office partitions, computer facilities, furnishings, and so on, must all be provided.A complicating factor is that there is an interdependence of activities. In other words, some parts of the project cannot be started until other parts are completed. For example, Global cannot construct the interior of an office before it has been designed. Neither can it hire new employees until it has determined its personnel requirements.The necessary activities and their necessary predecessors (due to interdependence) are listed below. Three estimates are made for the completion time of each activity—the minimum time, most likely time, and maximum time.StartEndGlobal Oil Simulation with Crystal Ball®Step #1 (Setup Spreadsheet)Step #2 (Define Assumptions—., random variables)Each of the random activity times (B, C, D, E, G, and I) is assumed to follow the triangular distribution.Global Oil Simulation with Crystal Ball®Step #3 (Define Forecast—., output)Cell J15 is the forecast cell:Step #4 (Choose Number of Trials)500 trials were run. In addition, Sensitivity Analysis was enabled in the Options of the Run Preferences dialogue box. This allows for the generation of sensitivity analysis results later.Step #5 (Run Simulation)Step #6 (View Results)Additional Results Available with Crystal Ball®Slide the triangles below the histograms to determine the probability that the output (project duration) is less than a certain value ., a deadline), greater than a certain value, or between any two values (by sliding both triangles).Alternatively, you can type in values for the lower bound or upper bound to determine the probability. You can also type in a probability (in “Certainty”), and it will determine the range that has that probability.There is a 79% chance the project will be completed within 150 days. There is a % chance that the project will take more than 160 days.Sensitivity ChartChoose “Open Sensitivity Chart” in the Run menu. Note that thischart is only available if y ou selected the “Sensitivity Analysis” option under Run Preferences. This chart gives an indication as to which random variables (activity times) have the greatest impact on the output cell (project completion time).Variability in activity E has the greatest impact on overall project duration, followed by activity D, C, I, and B. Variability in activityG has almost no impact.Fitting a DistributionCrystal Ball can be used to “fit” a distribution to data.The following data has been collected for the previous 100 phone calls to a mail-order house:(80 rows have been hidden)Fitting Data to a DistributionUsing Crystal Ball® to fit data to a distribution1. Select a spreadsheet cell.2. Choose Define Assumption.3. Click the Fit button, then select the source of the fitteddata.4. Click the Next button, then select the distributions to try tofit.5. Click OK.Interarrival TimeService Time。
Crystall_Ball模拟软件
实验次数 均值 中数 众数 标准差 方差 偏度(描述变量取值分布对称性的统计量) 峰度(描述变量取值分布形态陡缓程度的统计量) 变异系数 平均标准误差
4 示例－费瑞迪报童问题
通过前面的模拟，设定了弗瑞迪每天《金融日 报》的定购数量为60份，因为这个定购量是一 个能够满足需求又不会剩余大量未出售报纸的 一个合理折中值
然而通过目前的模拟，还不能说明60是否是最 大化其日均利润的最优定购量。利用Crystal Ball软件中的OptQuest最优化模型可以搜索 最佳定购量。
4 示例－费瑞迪报童问题
用决策表制定决策
在40到70之间的哪个订购量能够最大化每天的平均利润呢？ 比较合理的做法是试验订购量的可能值的各个样本，如 40,45,…,70。
4 示例－费瑞迪报童问题
定义预测单元格：计算机模拟的电子表格模型并没有包括目
标单元格，但是预测单元格可以实现这一作用。定义预测单元格 的步骤：
（1）选中一个单元格； （2）单击Crystal Ball工具条中的Define Forecast按钮，从而弹出
定义预测对话框（如图8-14所示） （3）这个对话框可以用来输入一个名字标签，并且定义预测单元格的
3 Crystal Ball工具条
Define Define
Run Start
Reset
Forecast Trend
Assumptions Forecast Preferences Simulation Simulation Windows Chart
4 示例－费瑞迪报童问题
问题描述
成本数据
每份报纸成本费用1.50美元 售价2.50美元 未出售的报纸退款0.50美元
第三步对话框用来制定决策表的选项。第一个输入方框记录了对 于每一个决策变量的值所要运行模拟的次数。Crystal Ball会在 定义决策变量对话框所制定的范围内平均分布数值。对于弗瑞迪 报童问题，数值的范围是40到70，在第三步对话框中输入数字7 就会选择40、45、50、55、60、65、70这七个订单量的数值 进行模拟。 最后一步就是单击Start按钮。
crystal ball使用指导
crystal ball使用指导Crystal Ball使用指导Crystal Ball是一种常用的预测和决策支持工具，它基于蒙特卡洛仿真技术，可以对不确定性进行建模和分析。
下面将介绍一些使用Crystal Ball的指导，帮助您更好地利用这一工具进行预测和决策。
一、数据准备在使用Crystal Ball之前，首先要准备好相应的数据。
这些数据可以是历史数据、统计数据或者是专家意见。
确保数据的准确性和完整性非常重要，因为这些数据将直接影响到Crystal Ball的分析结果。
二、建立模型在Crystal Ball中，模型是指对问题进行描述和建模的过程。
模型的建立需要根据具体问题的特点来确定。
首先需要确定决策变量和随机变量，然后建立它们之间的关系。
在建立模型时，要保证模型的可靠性和合理性。
三、运行仿真在完成模型建立后，就可以进行仿真运行了。
Crystal Ball使用蒙特卡洛仿真技术，通过随机抽样来模拟不同可能的情况。
这样可以得到一系列可能的结果，并对其进行统计分析。
四、分析结果Crystal Ball提供了多种统计分析方法，可以帮助用户对仿真结果进行分析和解释。
常用的分析方法包括概率分布分析、敏感性分析和决策树分析等。
通过这些分析，可以得到关键决策变量的概率分布、敏感性程度以及最优决策方案等信息。
五、结果解释和应用在分析结果之后，需要对结果进行解释和应用。
Crystal Ball提供了可视化工具，可以将分析结果以图表的形式展示出来，帮助用户更好地理解和应用结果。
同时，还可以通过对结果的解释和讨论，对决策方案进行优化和调整。
六、风险管理Crystal Ball除了用于预测和决策支持，还可以用于风险管理。
通过对不确定性的建模和分析，可以帮助用户识别和评估潜在的风险，并采取相应的措施进行风险管理和控制。
七、案例分析以下是一个使用Crystal Ball进行预测和决策的案例分析。
假设某公司要决定是否投资于某个新项目。
第8章-Crystall-Ball模拟软件PPT课件
8.4 示例－费瑞迪报童问题
用决策表制定决策
在40到70之间的哪个订购量能够最大化每天的平均利润呢？ 比较合理的做法是试验订购量的可能值的各个样本，如 40,45,…,70。
利用决策表工具可以执行这个工作，具体的步骤如下：
（1）选择包含决策变量的单元格； （2）如果单元格中还没有数值，任意输入一个数值； （3）点击Crystal Ball工具条上的定义决策变量按钮，弹出定义
4481维数的灾难研究的问题中相关变量个数高达数百甚至数千难度随维数的增加呈指数增长蒙特卡罗方法的计算复杂性不依赖于维数主要步骤建立各种估计量5582利用crystalball软件进行模拟的步骤1建立电子表格模型2规定关于概率变量的假设3规定预测单元即相关的输出变量4设定重复次数5运行模拟6解释结果6683crystalballdefineassumptionsdefineforecastrunpreferencesstartsimulationresetsimulationforecastwindowstrendchart7784问题描述newsboy8884建立相关变量的工作表绿色单元格表示随机变量黄色单元格表示决策变量9984定义假设单元格
9
8.4 示例－费瑞迪报童问题
定义预测单元格：计算机模拟的电子表格模型并没有包括目
标单元格，但是预测单元格可以实现这一作用。定义预测单元格 的步骤：
（1）选中一个单元格； （2）单击Crystal Ball工具条中的Define Forecast按钮，从而弹出
定义预测对话框（如图8-14所示） （3）这个对话框可以用来输入一个名字标签，并且定义预测单元格的
决策变量对话框； （4）为决策变量的模拟数值定义下限和上限； （5）选择连续分布或者离散分布，定义决策变量是连续的还是离
化学实验制作水晶结晶实验
化学实验制作水晶结晶实验水晶结晶实验是一项经典的化学实验，通过溶解物质并使其重新结晶形成水晶，展示出美丽的结晶形态。
本文将介绍如何进行水晶结晶实验，并提供详细的实验步骤和操作方法。
材料准备：1. 高纯度结晶试剂（如硫酸镁、硫酸钾等）2. 蒸馏水或高纯度水3. 温度可控的容器（如玻璃烧杯、烧瓶等）4. 搅拌棒或玻璃棒5. 过滤纸或滤纸漏斗6. 显微镜（可选）实验步骤：1. 准备容器：选择一个温度可控的容器，保证容器内外温度的稳定。
可以在恒温水浴中进行实验，或者根据实验要求调节加热设备的温度。
2. 溶解试剂：称取一定质量的结晶试剂，例如硫酸镁，加入足够的蒸馏水或高纯度水中。
根据试剂的溶解度，在适当的温度下搅拌溶解，直至试剂完全溶解。
3. 过滤溶液：使用过滤纸或滤纸漏斗过滤溶液，去除其中的杂质或未溶解的物质。
保持滤液的透明度，这对于后续结晶的形成非常重要。
4. 结晶形成：将过滤后的溶液静置于容器内，等待结晶的形成。
这个过程可能需要一段时间，可以放置到恒温箱中提高结晶的速度。
在等待的过程中，可以观察溶液的变化，以及结晶的形态。
5. 结晶收集：当结晶完全形成后，使用过滤纸或滤纸漏斗将结晶分离出来，并用冷蒸馏水洗涤结晶，以去除表面附着的杂质。
6. 结晶鉴定：观察收集到的结晶样品，使用显微镜可以更加清晰地观察结晶的形态和细节。
可以与已知的水晶样品进行对比，以判断结晶的纯度和成分。
实验注意事项：1. 实验过程中要注意安全，避免试剂溅入眼睛或皮肤接触。
实验室操作应符合安全规范，佩戴必要的防护设备。
2. 温度控制很关键，在结晶的过程中保持适当的温度，可以促进结晶的形成。
3. 结晶的形态与溶液的浓度、温度和其他物理条件密切相关。
可以尝试不同条件下的实验，观察不同条件下结晶的差异。
4. 结晶试剂的选取也可以根据需要进行调整，不同试剂可能会产生不同形态的结晶。
总结：水晶结晶实验是一项非常有趣和美丽的化学实验。
通过溶解试剂并使其重新结晶，我们可以观察到结晶的形态和细节，体验到化学反应中的美妙和奇妙。
风险管理软件Crystal_Ball使用指导
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(typically theyou would later like Sensitivity Analysisto generate the under Options in Preferences.Monte-Carlo Simulation with Crystal Ball用水晶球软件进行蒙特卡洛模拟To run a simulation using Crystal Ball1. Setup Spreadsheet1．设定数据表Build a spreadsheet that will calculate the performance measure (e.g., profit) in terms of the inputs （random or not）. For random inputs, just enter any number. Hwbpsm。
K 通过建立数据表可以对输入数据（随机的，非随机）进行评估。
随机数据的输入，输入任意数即可。
2. Define Assumptions —i.e., random variablesDefine which cells are random, and what distribution follow. 274B0W。
R2．定义假设的前提—例如，随机变量确定那些单元格的数据时随机的，这些数据应该服从什么样的分布3. Define Forecast —i.e., output or performancemeasureDefine which cell（s） you are interested in forecasting performance measure, e.g., profit）.biNjnie 。
3．预测结果的确定—例如，数据输出或者性能的测定确定哪些单元格的数据是你想预测的（典型的性能指标，例如，利润）4. Choose Number of TrialsSelect the number of trials. IfSensitivity Analysis chart, choose Run 4. 选择试验的次数5DJxkmF。
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Crystal Ball实验操作过程
实验一：
一、数据录入与导入
双击CB快捷方式图标或直接打开Excel打开软件。
前面提到过Crystal Ball软件是在Excel 里的一个插件，所以双击打开后是Excel的界面，如下图：
图 1
用户可以在该界面中直接录入数据，也可以左击右上角的符号，选择打开，将原有Excel表格中的数据直接导入到带有Crystal Ball插件的电子表格中。
二、拟合分布
图2
(1)对数据进行标准化处理(减少原数据相互间的距离对拟合分布的影响)
通过Average计算每个分布工程样本数据的均值,然后各个样本数据除以相
应的均值,对数据进行标准化处理。
（2）拟合分布
选取表格区域，点击工具栏上“Run-Tools-Batch Fit”,如图3所示。
图3
在操作对话框中，选择“next”,至图4对话框对相应命令进行选择,可得到拟合过程的相关数据。
图4
注：对于卡方检验，水晶球软件计算p值，p值大于0.5一般表示紧密拟合；
对于科尔莫格洛夫-斯米尔诺夫检验，一般地，小于0.03的K-S值表明良好拟合；
对于安德森-达林检验，小于1.5的计算值一般表明拟合优良。
实验二:
一.按照实验一的操作,先将数据在Crystal Ball软件打开.
二、假设单元格概率分布的定义及相关操作
输入数据后，进行随机变量假设单元格概率分布的定义。
这里假设使用悲观时间的单元格来进行概率分布的定义。
（注：对于假设单元格的选择，并无太多的限制，因为定义各种概率的分布，是由相应的参数确定的，因此选择的假设单元格不同对结果并没有影响。
）有一点需要注意的是，选择假设单元格时，该单元格应当是一确定的数字，而不能是公式.
选定单元格（如单元格I2）后，点击工具栏上的，随即弹出图5，CB 软件中提供22种不同的分布可供选择，根据实验任务书的要求，第一和第二项分部分项工程服从三参数beta分布，因此，选择BtaPERT分布，并填入相应参数，即可完成对“基坑支护挖土方”的定义，如图6所示。
同理可完成其它分布的定义。
图5
图6
由于第3~8项同为三角分布，因此当完成第3项的定以后，选定I4单元格
（假定仍使用悲观时间列的单元格来进行定义），点击工具栏上的copy
data 按钮，然后选择I5~I9单元格，点击右侧的按钮，即可完成第4~8项的定义，同理可便捷地完成其他分部分项工程分布函数的定义。
三、确定关键线路
根据各分部分项的逻辑关系绘制出项目的单代号网络图，确定项目存在的线路，并用数学表达式表示出来，结果为：
线路1=I2+I3+I16+I18+I19+I20
线路2=SUM(I2:I7)+I14+I15+I19+I20
线路3=SUM(I2:I10)+I17+I18+I19+I20
线路4=I2+I3+I4+I5+I6+I7+I11+I12+I13+F12+I19+I20
关键线路为：=MAX(C21:I24)
四、输出变量预测单元格的定义及相关操作
所有假设单元格的概率分布定义后，须定义预测单元格。
所选择的预测单元格是由相关的变量假设单元格间经过一定的公式计算所得,即预测单元格必须是带有公式或数值的单元格，否则将出现如图7的提示界面。
图7
选中预测单元格后，点击工具栏中的Define Forecast, 进入Define Forecast对话框，可直接输入或点击按钮引用电子表格中的地址值设置预测单元格名称和度量单位（图23），点击OK后定义完成，该单元格变成蓝色（图9）。
本例中预测单元格是C25, 其公式是=MAX(C21:I24)，预测单元名字和度量单位分别是预测工期和days。
图8
图9
五、运行模拟相关操作
这里默认模拟次数为1000次，（模拟次数的设定详细可参考操作手册）选择，运行模拟。
运行模拟完成后将显示预测图。
图10显示的是1000次试验后输出变量预测工期的直方形预测图，选择view菜单可改变预测图的类型，CB主要提供频率预测图（frequency）、累计频率预测图（cumulative）、频数分布预测图（percentiles）、统计量报告预测图（statistics）。
图10
五、风险分析相关操作
任务书要求项目在1077天内完工的概率，如图11，只需在右侧单元格中填入1077，单击回车，即可得出其概率为26.64%。
图11
求合理工期（假设完工概率80%以上为合理），需将右侧小三角往回拉，拉回正无穷大的状态下，在中间的单元格中填入80，单击回车，将左侧的小三角拉回负无穷状态，再次填入80，单击回车，即可求得合理工期为1110天（1109.42）。
图12
六、借助敏感性分析对工期进行优化
如图13，打开敏感性分析结果（图14），可直观看出项目中最敏感性因素为“塔楼室外装修与安装”，该分部分项工程对工期的影响程度最大，因此可从该分部分项工程着手，采取赶工或改进施工技术，缩短工期从而达到更快地缩短工程项目总工期的目的。
进行调整后，从新拟合分布和对总工期进行拟合，项目在1077天的完工概率将得到改变，同时各分部分项工程的敏感性顺序也将发生变化，可按照上述步骤多次操作，直至项目的完工概率满足要求。
图13 图14。