Data integrity: reasonableness

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Date:

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Quick Questions

Shade in the A or B circle for each question.

1. A student's age is recorded as 250 in a dataset. Is this value reasonable?

A No, it is not plausible for a person's age

B Yes, it is a valid number so it is reasonable

2. Which best describes data integrity: reasonableness?

A Values are stored in the correct data type only

B Values are sensible and plausible for what they describe

3. A reasonableness check on an age field uses a range of 0 to 120. Which value passes?

A -5

B 34

4. Which value fails a reasonableness check on a range of 0 to 100 for a test percentage?

A 135

B 87

5. What does a range check do when testing for reasonableness?

A Tests whether a value lies between a minimum and a maximum

B Tests whether a value is typed in capital letters

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1IF age < 0 OR age > 120 THEN reject		ABeing a valid number does not make a value reasonable. A negative age is implausible and should fail the check.
2age = 250		BAn unreasonable value because no person could be 250 years old
3A reasonableness check tests whether a value sits inside a sensible range		CA range-based reasonableness check that rejects any age outside 0 to 120
4A plausible age passes a reasonableness check on a range of 0 to 120		DThe range is too wide to be a useful reasonableness check, because an age of 250 would still be accepted. A sensible upper limit is about 120.
5Range check for age: 0 to 1000		Eage = 16
6age = -5 passes because it is a number		FIF mark >= 0 AND mark <= 100 THEN accept

Definitions

reasonableness

Fill in the Blanks

Complete each line of code by filling in the missing parts.

SELECT name FROM people WHERE age _ 120;

=IF(___(B2>=0,B2<=120),"OK","Check")

IF age < 0 __ age > 120 THEN DISPLAY "Age not reasonable" END IF

SELECT * FROM people WHERE age _______ 0 AND 120;

=_______(B2:B30,">120")

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A lo ← 200

B hi ← 120

C IF age >= lo AND age <= hi

D OUTPUT 'Reasonable'

Question 2

A INPUT age

B IF age >= 0 AND age <= 120

C OUTPUT 'Not reasonable'

D ELSE

E OUTPUT 'Not reasonable'

Question 3

A age ← 250

B valid ← FALSE

C IF age >= 0 AND age <= 120

D valid ← FALSE

E OUTPUT valid

Question 4

A hi ← 1200

B lo ← 0

C IF age < lo OR age > hi

D OUTPUT 'Check age'

Question 5

A INPUT age

B valid ← TRUE

C IF age < 0 AND age > 120

D valid ← FALSE

E OUTPUT valid

Answer Key

Data integrity: reasonableness

Section A: Quick Questions

A — No, it is not plausible for a person's age

B — Values are sensible and plausible for what they describe

B — 34

A — 135

A — Tests whether a value lies between a minimum and a maximum

Section B: Match the Pairs

IF age < 0 OR age > 120 THEN reject → A range-based reasonableness check that rejects any age outside 0 to 120

age = 250 → An unreasonable value because no person could be 250 years old

A reasonableness check tests whether a value sits inside a sensible range → IF mark >= 0 AND mark <= 100 THEN accept

A plausible age passes a reasonableness check on a range of 0 to 120 → age = 16

Range check for age: 0 to 1000 → The range is too wide to be a useful reasonableness check, because an age of 250 would still be accepted. A sensible upper limit is about 120.

age = -5 passes because it is a number → Being a valid number does not make a value reasonable. A negative age is implausible and should fail the check.

Section C: Definitions

reasonableness — Data is reasonable when its values are sensible and plausible for what they describe. An age of 250 fails a reasonableness check on a range, such as 0 to 120.

Section D: Fill in the Blanks

SELECT name FROM people WHERE age > 120;

=IF(AND(B2>=0,B2<=120),"OK","Check")

IF age < 0 OR age > 120 THEN
  DISPLAY "Age not reasonable"
END IF

SELECT * FROM people WHERE age BETWEEN
 0 AND 120;

=COUNTIF(B2:B30,">120")

Section E: Spot the Error

A — The lower limit of the range must be 0, not 200. With a lower limit above the upper limit of 120, no age could ever pass the reasonableness check. It should be lo ← 0.

C — This branch runs when the age is inside the range 0 to 120, so the value is reasonable. The output should be OUTPUT 'Reasonable'.

D — When the age is inside the range 0 to 120 the value is reasonable, so valid must be set to TRUE. It should be valid ← TRUE.

A — An upper limit of 1200 is not a plausible human age, so an age of 250 would wrongly pass the check. The upper limit should be hi ← 120.

C — No age can be below 0 and above 120 at the same time, so the condition is never true and an age of 250 would pass. It needs OR: IF age < 0 OR age > 120.