Session 6 Managerial Spreadsheet Modeling -- Prof. Juran1.
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Transcript of Session 6 Managerial Spreadsheet Modeling -- Prof. Juran1.
Session 6
Managerial Spreadsheet Modeling -- Prof. Juran 1
Managerial Spreadsheet Modeling -- Prof. Juran 2
Outline
• Facilitating Change through Graphical Controls
• Restricting Change
Managerial Spreadsheet Modeling -- Prof. Juran 3
Easier “what if” experimentation– Less downtime when making changes– Mouse click vs. keyboard entry
Increased comprehension– Show effects of changes continuously
– Especially when tied into a graph– Remove the distracting intermediate steps of Excel data
entry
Why Bother Facilitating Change?
Managerial Spreadsheet Modeling -- Prof. Juran 4
“Vanilla” Excel – No VBA macros
But first: File | Options | Customize Ribbon | Developer
Graphical Controls
Managerial Spreadsheet Modeling -- Prof. Juran 5
Developer | Controls | Insert | Forms Controls
Graphical Controls
Managerial Spreadsheet Modeling -- Prof. Juran 6
Alternative: ActiveX Controls– More powerful, more options– Much less easy to use– Avoid, unless you know OOP– Toggle Design Mode
Graphical Controls
Managerial Spreadsheet Modeling -- Prof. Juran 7
After clicking on the button on the Forms Control, the cursor will change to a crosshair (+).
Move to where you want the control to be.
Click and hold the left mouse button, move to the opposite corner, and release the button.
Tip: To ensure that all the controls are the same size, right-click, copy and paste the first one.
The Magic: Right-click Format Control | Control | Cell link– Ties the graphical control to a value in a cell.
The rest of the spreadsheet can now key off of the value in that cell.
Selecting the Controls
Managerial Spreadsheet Modeling -- Prof. Juran 8
Spin Buttons are better for a few values.
Scroll Bars are better when there is a wide range of choices.
Spin Buttons and Scroll Bars
Min and max values that the cell can assume
Which spreadsheet cell contains the value? (Critical!)
Each time you click on an arrow
Each time you click on the scroll region (scroll bar only)
Sure; I’m not driving …
Managerial Spreadsheet Modeling -- Prof. Juran 9
Cell values can only be non-negative integers.
Example 1: Allow the inflation rate to vary between 2.0% and 4.5%, by 0.1%.
Example 2: Allow the confidence level to take on one of five values: 90%, 95%, 97.5%, 99%, or 99.5%.
Overcoming their Limitations
Managerial Spreadsheet Modeling -- Prof. Juran 10
Allows a choice from a pull-down menu– Similar to Data Validation with a list– List Box: Choices are always displayed
Combo Box and List Box
Column which contains the allowable choices
Contains the index number (1 – ?) of the current choice
To be displayed at any one time
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The font is too small.– Make everything small, then view at 200%?– Use ActiveX Controls instead.
Cannot use with protected cells.
Input range must be a column, not a row.– Unlike Data Validation.
Limitations
Managerial Spreadsheet Modeling -- Prof. Juran 12
Use in combination with the Choose function to select from among various scenarios.
– Soon we’ll learn about the powerful Index function.
Use in scenario planning
123456789
101112
A B C D E F G
Expected Profit $ 3.2 million Plant Size Decision 1
Demand Level 2
1 2Large Plant Small Plant Large Plant
1 High Demand 7.2 1.1 Small Plant2 Moderate Demand 3.2 3.13 Low Demand -4.8 4.1
Demand
Decision
=IF(G2=1,CHOOSE(G4,D10,D11,D12),CHOOSE(G4,E10,E11,E12))
Managerial Spreadsheet Modeling -- Prof. Juran 13
Another way to go: VLOOKUP or HLOOKUP
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2
3
4
5
6
7
8
9
10
11
12
A B C D E F G
Expected Profit $ 1.1 million Plant Size Decision 2
Demand Level 1
Decision
1 2Large Plant Small Plant Large Plant
Demand 1 High Demand 7.2 1.1 Small Plant2 Moderate Demand 3.2 3.13 Low Demand -4.8 4.1
=HLOOKUP(G2,$D$8:$E$12,G4+2,0)
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Choose(index, value1, value2, …)
– If index = 1, return value1; if it is 2, return value2; and so on.
– If index < 1 or greater than the number of the last value in the list, Choose returns the #VALUE! error value.
– If index is a fraction, it is rounded down before being used.
The Choose() function
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For options with two choices.– Cell link is True if box is checked, False otherwise– Right-click and choose Edit Text to change the label
– Or delete the text and enter it into a cell instead, for more formatting options.
Check Boxes
Cell value will either be True or False.
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If(•), And(•), Or(•), and Not(•)
Work with conditions (e.g., “B3 = 12”) that are either True or False.
Cells can be True or False as well.
Check Boxes and Logical functions
1
2
3
4
5
A B CCheck Box Going to Cornell was the best decision I ever made.
FALSE
Debbie present?
1
2
3
4
5
A B CCheck Box Going to Cornell was the second best decision I ever made.
TRUE
Debbie present?
Managerial Spreadsheet Modeling -- Prof. Juran 17
Used when selecting one — and only one — of a set of choices.
– Construct just like a Check Box.– Cell link is the index of the Radio Button (1 – ?), just like a
Combo Box.– If you have more than one set of Radio Buttons, use the Group
Box to “corral” connected sets.
Example: Decision Analysis (as before)
Option (Radio) Buttons
12345678910111213
A B C D E F G H
Expected Profit $ 3.1 millionPlant Size 2 Small Plant
Demand Level 2 Moderate Demand
Decision1 2
Large Plant Small PlantDemand 1 High Demand 7.2 1.1
2 Moderate Demand 3.2 3.13 Low Demand -4.8 4.1
Plant Size
Demand Level
HighModerate
Low
Large
Small
=IF(G3="Large Plant",CHOOSE(F5,D11,D12,D13),CHOOSE(F5,E11,E12,E13))
Managerial Spreadsheet Modeling -- Prof. Juran 18
Restricting Change
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Spreadsheet users unknowingly introduce errors when they make changes to (formulas in) an existing spreadsheet.
Four methods to reduce inadvertently-introduced errors– Hide areas from the user– Protect areas from being changed– Warn about suspicious data before it’s entered– Document those changes that are made
Why Restrict Change?
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Rows, columns, and entire worksheets can be hidden (and unhidden).
– For aesthetic as well as security reasons.– Home | Format | Hide or Unhide | (Un) Hide
{Rows/Column/Sheet}– Rows and columns are set to zero height/width.
Make them invisible.– Set text color to background color.– Hide them under a chart or picture.– Home | Number | Custom | Type: ;;;– Downside: Makes them more susceptible to overwriting.
Hiding Regions
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All cells are Locked by default.
Unlock the cells you want the user to be able to change.
– Home | Cells | Format | Format Cells | Protection | Locked
– If there are only a few cells you want to protect:
Select all the cells on the worksheetType Ctrl-A, orClick on the box between A and 1 at the top left.
Unlock them all (as above). Then select and re-lock those
few cells you want to protect.Home | Editing | Find & Select | Formulas will select all of the equations.
Protecting Cells from Change: Step 1
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At this point you need to enable protection for the cells you locked in Step 1.
Home | Cells | Format | Protect Sheet– Don’t bother with passwords (unless
your spreadsheet is proprietary).– Undo with Home | Cells | Format |
Unprotect Sheet
You’re trying to prevent inadvertent changes.
Protecting Cells from Change: Step 2
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In order to hide your formulas from viewing or editing:– Select those cells whose formulas you want to hide,– Home | Cells | Format | Format Cells | Protection |
Hidden, and– Home | Cells | Format | Protect Sheet
Cells still can be overwritten.– Unless, of course, they’re Locked as well.
Side Note: Hiding Formulas
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File | Save As | Excel Workbook | Tools | General Options
Adding Passwords to Workbooks
– Password to open: Required to even open the file.
– Password to modify: Required to be able to modify the file; otherwise it opens as a read-only file.
– Don’t rely on passwords for absolute protection.
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Avoid common passwords, which include:– 16%: First name (zack)– 14%: Keyboard pattern (qwerty, 1qaz2wsx)– 5%: Pop-culture reference (pokemon, klingon, legolas), or– looks like a password (blink182, rush2112, 8675309)– 4%: Variation on “password” (passw0rd, drowssap)– 4%: Nearby objects (samsung, dell)– 3%: “Emo” words (obscenities, ihateyou)– 3%: Indifference words (whatever, nothing)– 1%: Movie passwords (letmein, trustno1, joshua, ramsesii)– 1%: Sports related (jordan23)
Secure: First letters of some phrase: mni0k0k
Secure: Four random words: correct horse battery staple
Passwords
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Low-tech: put an If(•) function in a nearby cell:– Example: A1 contains self-reported GPA.– Format A2 to be bold red, and define– A2 = If(A1<4.333, "", "Reported GPA is too
high!")
High-tech Version: Data | Data Tools | Data Validation– Permits only selected values to be entered into a cell.– Only works with unprotected worksheets.– Not absolutely foolproof: You can always paste any value
into a cell that is protected by data validation.
Warning of Bad Data
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Settings tab:
Data Validation
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Note that the list can be separated by commas — the values don’t need to be placed on the spreadsheet.
Data Validation: Choose from a List
1
2
3
A B C
Confidence level 99.0%
Could instead refer to a range of values elsewhere in the worksheet.
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Can use Data Validation instead of Combo Boxes.
Good application of VLOOKUP(•) and IF(•).
Scenario Planning (revisited)
123456789101112
A B C D E F G
Expected Profit $ 3.1 million Plant Size Decision Small Plant
Demand Level Moderate Demand
1 2Large Plant Small Plant Large Plant
1 High Demand 7.2 1.1 Small Plant2 Moderate Demand 3.2 3.13 Low Demand -4.8 4.1
Decision
Demand
=IF(E2="Large Plant",VLOOKUP(E4,$C$10:$E$12,2,0),VLOOKUP(E4,$C$10:$E$12,3,0))
Managerial Spreadsheet Modeling -- Prof. Juran 30
Data Validation: Getting Fancy
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If you can’t restrict changes, can you at least keep track of them?
Helpful for group projects, too.
Review | Changes | Track Changes | Highlight Changes– Track changes while editing.
Documenting Changes
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The goal of restricting change is to reduce the inadvertent introduction of errors. Techniques include:
– Hide cell values and/or formulas.– Protect the cells against being changed.– Protect the workbook from being opened without
authorization.– Validate that only reasonable data can be entered.– Track the changes that are made.
Take-aways
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Hands-on practiceMake a table of your core courses, and the grade you deserved in each.
Then use a Combo Box and the Choose function to list the grade for any selected course in an adjacent cell.
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Use a spin button to allow a cell to be:– An integer between 3 and 12.– An integer between -10 and +15.– The third Friday for any of the next six months (tricky).
Use a scroll bar to allow a cell to take on the values -10.0%, -9.9%, ..., 24.9%, 25.0%.
Hands-on practice
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Use Check Boxes and/or Radio Buttons to identify purchased marshmallows as either large or small. Add a tax of 8.5% to large marshmallows (which are considered candy) but not small marshmallows (which aren’t).
Use Radio Buttons to allow the user to pick one of the first four numbers. If they pick 3, print the message “75% of all people pick 3.”
Or whatever.
Hands-on practice
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Practice the different ways of hiding information– Hiding rows, columns, and worksheets– Changing the text color to the background color– Changing the number format to ;;;– Change the cell protection to Hidden
Create a protected worksheet where the user can change all but three cells.
Create a protected worksheet where the user can change only two given cells.
Hands-on Practice
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Use data validation to:– Allow only integers between 21 and 37.– Allow only even numbers.– Allow only the values: Base Case, Optimistic, and
Pessimistic.– Mess around with the Error Alert and the Input Message.
Track changes to see how the documentation works.
Hands-on Practice
Managerial Spreadsheet Modeling -- Prof. Juran 38
• Deliverable: Pro Home Builders• Keyboard Shortcut quiz
For Next Time