Useability principle: effectiveness
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Which description best matches the useability principle of effectiveness?
2. A student uses a school canteen app to order lunch, but the app drops one item from every order. What is the problem?
3. Which change would make a timetable app MORE effective for finding a class room?
4. True or false: An interface that causes many user errors can still be effective.
5. Which is a measure of effectiveness during user testing?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1effectiveness | AThe result is inaccurate, so the interface is not effective. The marking must give correct results. | |
| 2task_completion_rate = done / attempts | BMeasures effectiveness by showing what share of attempted tasks users finished successfully. | |
| 3An effective interface gives accurate results, so the total shown must match what the user entered. | CA useability principle: users can complete their tasks accurately and completely, with correct results. | |
| 4An effective interface needs few steps and few errors, so users can finish a task quickly with one clear action. | DThe user cannot complete the task, so the interface is not effective. The Pay button should be visible and reachable. | |
| 5Checkout form: user can't submit because the Pay button is hidden below the screen | Esteps = 3 # select item, pay, confirm | |
| 6Quiz app marks a correct answer wrong and gives the student 0 out of 10 | Fassert total == price * quantity |
C
Definitions
effectiveness
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
if ___(name) == 0:
showError("Name is required")
2.
total = price _ quantity
showTotal(total)
3.
if not age._______():
showError("Numbers only")
4.
if paid ___ shipped:
status = "complete"
5.
if newSteps _ oldSteps:
print("Fewer steps")
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
done = 18
B
tried = 20
C
rate = done / tried * 100
D
if rate <= 90:
E
print("Effective")
Question 2
A
total = 12.50 + 7.25
B
shown = round(total, 0)
C
if shown == 19.75:
D
print("Accurate")
Question 3
A
steps_old = 9
B
steps_new = 4
C
saved = steps_new - steps_old
D
print("Steps saved:", saved)
Question 4
A
results = [True, False, True]
B
errors = 0
C
for ok in results
D
if not ok:
E
errors += 1
Question 5
A
task = "Book a ticket"
B
booked = True
C
paid = True
D
complete = booked or paid
E
print(task, complete)
Answer Key
Useability principle: effectiveness
Section A: Quick Questions
Q1
B — Users can complete their tasks accurately and completely
Q2
B — The app is not effective because the task is not completed accurately
Q3
A — Reducing the steps from five taps to two taps
Q4
A — False: many errors mean users struggle to complete tasks correctly
Q5
A — The percentage of users who complete the task correctly
Section B: Match the Pairs
Q1
effectiveness → A useability principle: users can complete their tasks accurately and completely, with correct results.
Q2
task_completion_rate = done / attempts → Measures effectiveness by showing what share of attempted tasks users finished successfully.
Q3
An effective interface gives accurate results, so the total shown must match what the user entered. → assert total == price * quantity
Q4
An effective interface needs few steps and few errors, so users can finish a task quickly with one clear action. → steps = 3 # select item, pay, confirm
Q5
Checkout form: user can't submit because the Pay button is hidden below the screen → The user cannot complete the task, so the interface is not effective. The Pay button should be visible and reachable.
Q6
Quiz app marks a correct answer wrong and gives the student 0 out of 10 → The result is inaccurate, so the interface is not effective. The marking must give correct results.
Section C: Definitions
Q1
effectiveness — A useability principle: users can complete their tasks accurately and completely, with correct results, few steps and few errors.Section D: Fill in the Blanks
Q1
if len(name) == 0:
showError("Name is required")Q2
total = price * quantity
showTotal(total)Q3
if not age.isdigit():
showError("Numbers only")Q4
if paid and shipped:
status = "complete"Q5
if newSteps < oldSteps:
print("Fewer steps")Section E: Spot the Error
Q1
D — Effectiveness needs a HIGH task completion rate. The check should be rate >= 90, not <=, otherwise low completion would be called effective.
Q2
B — Rounding to 0 decimal places loses the cents, so the result is not accurate. It should be round(total, 2) to keep the correct value.
Q3
C — Steps saved is old steps minus new steps. Reversing them gives a negative number, which wrongly suggests the new design adds steps.
Q4
C — A for loop line must end with a colon. It should be for ok in results: so the loop can count the errors users made.
Q5
D — A task is only complete when every step is done, so it needs and. Using or would report success even if the user never paid.