Data quality: accuracy

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. A student types a customer's age as 215 instead of 25. What is the problem with this data?

A It is accurate because it was entered into the system

B It is inaccurate because it does not match the real age

2. Which statement best describes accurate data?

A Correct and free from errors, so it matches the real-world fact

B Stored in a large database that many people can access

3. A faulty thermometer reads 5°C too high every time. Is the temperature data accurate?

A Yes, because the readings are all consistent

B No, the measurement error makes the values incorrect

4. A school's contact list still shows a student's old mobile number after they changed it. What is wrong with the data?

A It is out of date, so it is no longer accurate

B It is still accurate because it was correct once

5. How can you check whether a value in a dataset is accurate?

A Compare it against a trusted source

B Check that it looks neat and well formatted

Match the Pairs

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

Left column		Right column
1Age: 215		AAn out-of-date value: the person has since moved, so the stored fact is no longer correct
2Address: 12 Oak St (moved in 2019)		BA typing error: the student meant 15 or 21, so the value does not match the real fact
3Checking data against a trusted source helps confirm it is accurate		CA typing error added an extra digit, so the data is inaccurate and must be corrected by checking the source
4A faulty measuring tool can make data inaccurate even when it is typed in correctly		DThe value is out of date, so the data is inaccurate and needs to be updated from a trusted source
5Height (cm): 1750 (should be 175)		EScale reads 3 kg when the real weight is 2 kg
6Phone: 0412 345 678 (changed last year, never updated)		FCompare student marks to the official school report

Definitions

accuracy

Fill in the Blanks

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

=__(B2=Master!B2,"Accurate","Check")

IF age < 0 __ age > 120 THEN DISPLAY "Check age" END IF

=___(B2-C2)<=0.5

=IF(A2__B2,"Typo","OK")

=IF(_____()-D2>365,"Out of date","Current")

Spot the Error

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

Question 1

A source ← 2005

B typed ← 2050

C IF typed ≠ source THEN

D OUTPUT "Data is accurate"

E ENDIF

Question 2

A trusted ← 36.6

B sensor ← 38.9

C diff ← ABS(sensor - trusted)

D IF diff < 0.5 THEN

E OUTPUT "Faulty reading"

Question 3

A scale ← 62.5

B actual ← 60.0

C error ← scale + actual

D OUTPUT "Error: ", error

Question 4

A birth_year ← 2009

B age ← 2025 + birth_year

C OUTPUT "Age: ", age

Question 5

A tolerance ← -0.5

B diff ← ABS(reading - actual)

C IF diff ≤ tolerance THEN

D OUTPUT "Accurate"

Answer Key

Data quality: accuracy

Section A: Quick Questions

B — It is inaccurate because it does not match the real age

A — Correct and free from errors, so it matches the real-world fact

B — No, the measurement error makes the values incorrect

A — It is out of date, so it is no longer accurate

A — Compare it against a trusted source

Section B: Match the Pairs

Age: 215 → A typing error: the student meant 15 or 21, so the value does not match the real fact

Address: 12 Oak St (moved in 2019) → An out-of-date value: the person has since moved, so the stored fact is no longer correct

Checking data against a trusted source helps confirm it is accurate → Compare student marks to the official school report

A faulty measuring tool can make data inaccurate even when it is typed in correctly → Scale reads 3 kg when the real weight is 2 kg

Height (cm): 1750 (should be 175) → A typing error added an extra digit, so the data is inaccurate and must be corrected by checking the source

Phone: 0412 345 678 (changed last year, never updated) → The value is out of date, so the data is inaccurate and needs to be updated from a trusted source

Section C: Definitions

accuracy — Data is accurate when it is correct and free from errors, so it matches the real-world fact it records. Typos, faulty measurements and out-of-date values make data inaccurate.

Section D: Fill in the Blanks

=IF(B2=Master!B2,"Accurate","Check")

IF age < 0 OR age > 120 THEN
  DISPLAY "Check age"
END IF

=ABS(B2-C2)<=0.5

=IF(A2<>B2,"Typo","OK")

=IF(TODAY()-D2>365,"Out of date","Current")

Section E: Spot the Error

D — The typed year (2050) does not match the trusted source (2005), so a typing error has made the data inaccurate. Line 4 should output "Typing error", not say the data is accurate.

D — A large difference from the trusted value signals a measurement error. The condition should be diff > 0.5. Using < flags readings that are actually close to correct.

C — The measurement error is the difference between the reading and the true value, so it should be scale - actual. Adding them gives a meaningless number.

B — Age is found by subtracting the birth year from the current year, so it should be 2025 - birth_year. Adding gives an impossible age and the data would be inaccurate.

A — A tolerance is the allowed size of an error, so it cannot be negative. With -0.5, no reading could ever pass the accuracy check. It should be 0.5.