Spreadsheet Models for Managers

Problem Set 13Session Links
Using Macros I

Be sure to check the list of worksheet functions that are needed for the homework assignments, to see which new functions (if any) might help with this assignment.

For a quick way to copy homework problem data into your homework solution, see “Avoid retyping homework problem data.”

Remember that some problems are slight extensions of what we show you in class, in the demonstrations and in the session notes, and some problems are somewhat ambiguous. This is intended to parallel what you’ll frequently encounter at work. If you feel a bit confused, there are some things you can do to help clarify things.

Before attempting this homework, you might find it helpful to read about:

• Excel Macros in Visual Basic for Applications

Numbers in square brackets to the right of the problem numbers indicate point values.

Write a macro that computes, for any number, the multiple of 100 that’s nearest to that number. Call your macro “Round100”. For example, Round100(712) should return 700. You can assume that the argument to your macro is always a number. Your macro should round to the next largest 100 if the number ends in 50 or more. The behavior for negative numbers should be symmetric. That is, for any x, Round100(-x) should be the same as -Round100(x). Use your macro to demonstrate the following results:

x Round100(x) 457.2 500 0.0 0 100.0 100

Your result should be a single 4x1 range.

The price schedule provided to Jersey Fried Chicken for cases of fried chicken buckets offers discounts depending on the number of cases of buckets ordered. The schedule is shown in the table below, which is reproduced from Problem 11.3.

Quantity Price 1-399 $21.00 400-1199 $18.00 1200 or more $16.90

Write a macro called BucketPrice which accepts a single argument that represents the quantity ordered, and returns a value equal to the price of one case of buckets. Your macro should assume that its argument is any number greater than or equal to 1. If it receives an argument that isn’t an integer, it should truncate the fractional part of the argument and return a result as if it had received an integer argument. Demonstrate your macro for these arguments: 276.00, 402.00, 432.47, 1898.20. Your result should be a single 4x1 range.

In the course of modeling operations at JFC, you find that you buy several products with three-step “staircase” price schedules as in Problem 13.2. You could write a separate function macro for each one, but that approach is wasteful and creates duplicated code. So you decide instead to write a single macro that’s invoked by each specialized macro. This is more reliable because it concentrates all the “thinking” in a single place.

The macro is called Staircase3, and does all the hard work for all three-step staircase pricing. It returns a single floating-point number — the unit price for the quantity specified. It accepts six arguments, ordered as follows:

quantity

The quantity whose unit price is to be determined by Staircase3. If it receives a value that isn’t an integer, it should truncate the fractional part of the argument and return a result as if it had received an integer argument.

price0

The undiscounted unit price. In the chicken buckets example, this argument would have the value $21.00. A floating-point number.

thresh1

The minimum number of units required for the first discount level. In the chicken buckets example, this argument would have the value 400. A large integer.

price1

The first level of discounted unit price. In the chicken buckets example, this argument would have the value $18.00. A floating-point number.

thresh2

The minimum number of units required for the second discount level. In the chicken buckets example, this argument would have the value 1200. A large integer.

price2

The second level of discounted unit price. In the chicken buckets example, this argument would have the value $16.90. A floating-point number.

Write the macro Staircase3, and demonstrate that it gives correct chicken-bucket prices for the chicken-bucket price schedule and these order quantities: 276.00, 402.00, 432.47, 1898.20. Your result should be a single 4x1 range.

Write a new macro BucketPrice3, that behaves exactly like BucketPrice, but computes its results by invoking Staircase3 internally. BucketPrice3 takes a single argument, and produces results identical to Price. Demonstrate its use with the four values 276.00, 402.00, 432.47, 1898.20. Your result should be a single 4x1 range.

Last Modified: Wednesday, 27-Apr-2016 04:15:26 EDT