Lesson 9: Using What if Analysis Justin Siddiqi, Jacob Manera, Michael Moreno

What is What If Analysis? What If Analysis is a powerful Excel feature that is able to experiment or find answers with your data This feature allows you to fill in missing data based on the information you already have It can be found on the Data Tab in the Data Tools section

Scenarios: What are they? A scenario is a set of values that Microsoft Office Excel saves and can substitute automatically on your worksheet. You can create and save different groups of values as scenarios on a worksheet and then switch between these scenarios to view the different results.

How to use Scenarios: Steps: 1. Identify the cells in the selected data can vary in each scenario. 2. Select the cells before clicking on creating a scenario in What if Analysis by clicking Data -> What If Analysis -> Scenario Manager on the ribbon or by pressing ALT +AWS. 3. To create your first scenario, in the scenario manager dialogue box, click add scenario. 4. Add as many scenarios as you need, then when you have the desired amount, exit the exit scenario manager.

Goal Seek Goal seek backsolves one cell value to reach a desired result in another cell. The solution can be saved as a scenario. In the Set Cell box you must choose a cell that contains a formula. This is the cell that is filled with the desired value In the To Value box insert the desired value In the By Changing Cell box choose the cell that will be altered to output the desired value (the cell with the missing/wrong value)

Excel Solver Add-on Solver must be downloaded and activated in Excel Solver backsolves the value for a cell with a formula Solver is used in optimization modeling, a process of finding the most desireable results for a formula It has 3 parts Objective- target cell that will be optimized/minimized Variable- cells that are changed to reach the desired value in the Objective Limitations/Constraints- ensures variable values cannot be changed to unrealistic or undesired data Constraints are added one at a time

Intro to Trendlines A trendline is a line fit to data in order to show the general course/tendency of data Trendlines are used to make predictions based off of data, which can be backwards, forward, or in between data. These predictions are made using the formula of the line, in this case, y=2.1071x-.5

How to Create a Trendline Steps: On the right side of your graph, click the plus sign and then click “Trendline” To Edit your trendline, click on the line, right-click it, and select “Format Trendline” You can make the trendline change colors, set a y-intercept, display statistical values such as r 2, and display the equation of the line to use in calculations

Predicting using a Trendline With the line of the chart, y=2.1071x-.5, you can predict a value. If x=8, what would our value of y be? y=2.1071(8) -.5=

Cautions using a Trendline Make sure that when predicting, only predict near the range of data you have For the range here of x=(1,7), you would not predict for x=50 because it is so far away from the data that your prediction would not be accurate. There is no data to support a value so far away from the rest of data

Practice Work Open up 9-26 in the Excel folder, turn to page 401 in the textbook, and do Exercise 9-26