A-LevelComputer ScienceSoftware development9618/22 · May/June 2025 · Q28 Marks

A program to calculate the pay of employees working for a company is being designed.

(a)Stepwise refinement has been used in the design of the program. Describe stepwise refinement.[2]
(b)One of the program modules used to calculate employees' weekly bonus pay has been completed. The amount of bonus pay they receive is based on the number of hours worked and the value of sales made as shown in the table. Bonus pay and value of sales are both in dollars. Hours worked Value of sales between 1 and 40 inclusive 2000 or less between 1 and 40 inclusive above 2000 above 40 2000 or less above 40 above 2000 Bonus pay 0 50 10 100
(b)(i)The module is tested using white-box testing. State two tests, using valid data, that can be used to test different paths through the program. Test one: Hours worked Value of sales Bonus pay Test two: Hours worked Value of sales Bonus pay[2]
(b)(ii)The program to calculate pay uses a number of modules which are each called from different places in the program. The program is to be tested using stub testing before all the program modules have been completed. Describe stub testing.[2]
(b)(iii)The program has been completed and compiles successfully. The program is tested using black-box testing. Identify and describe one type of error that black-box testing could detect. Type of error Description[2]

Mark scheme

Marking points from the official mark scheme (May/June 2025). The mark or mark type is shown in brackets.

[2] Mark as follows: 1. To increase the level of detail of the algorithm // To break the problem / task into smaller steps 2. ... until steps can be directly translated into lines of code // from which it can be programmed
[2] One mark for each of set test values Hours worked between 1 and 40 inclusive Sales value <= 2000 Bonus Pay: 0 Hours worked above 40 Sales value <= 2000 Bonus Pay: 10 Hours worked between 1 and 40 inclusive Sales value > 2000 Bonus Pay: 50 Hours worked above 40 Sales value above 2000 Bonus Pay: 100 max 2
[2] One mark per point • Simple modules are written to replace each of the unfinished modules. • Each simple module will return an expected value / will output a message to show it has been called.
[2] One mark for naming type of error and one mark for corresponding description Type of error: Description: Logic (error) Where the program does not behave as expected / Does not give expected result / An error in the logic of the algorithm Or Type of error: Run-time (error) Description: Max 2 The program performs an illegal operation

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