Keeping an untouched copy of the raw data

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Quick Questions

Shade in the A or B circle for each question.

1. Before you start cleaning a survey spreadsheet, what should you do first?

A Start fixing mistakes directly in the original data

B Keep the original data untouched on a Raw sheet and clean a copy

2. Which setup follows good practice for cleaning data?

A A sheet called Raw that is never edited and a sheet called Clean for changes

B One sheet called Data that you edit and save over each time

3. True or false: You should delete the Raw sheet once the Clean sheet looks finished.

A False - keep the Raw sheet in case you need to check or redo the cleaning

B True - the Raw sheet is no longer needed

4. Which file name best shows version numbers?

A survey_data_v2.csv

B survey_data_final_FINAL_new.csv

5. You accidentally delete a column while cleaning the Clean sheet. What does having a Raw sheet let you do?

A Nothing - the data is lost for good

B Copy the column back from the untouched Raw sheet

Match the Pairs

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

Left column		Right column
1=Raw!B2		ASheets: Raw \| Clean
2survey_data_v2.csv		BEditing the raw data permanently changes the original, so the deleted rows cannot be recovered
3Keep the original data safe by cleaning only a copy on a separate Clean sheet		COverwriting the same file name destroys the earlier version, so there is no backup to return to
4Save a new version of the file before each big cleaning step so you can go back		DA file name with a version number, showing this is the second saved version of the data
5Delete duplicate rows directly on the Raw sheet		Eresults_v1.xlsx -> results_v2.xlsx
6data.csv (saved over the old file after cleaning)		FPulls a value from the Raw sheet into the Clean sheet so the original cell stays untouched

Definitions

raw data copy

Fill in the Blanks

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

=TRIM(___!A2)

Raw: survey-v1.csv, Copy: survey-v_.csv

=______(Raw!B2)

=_____(Raw!A2)

=COUNTA(_____!A:A)=COUNTA(Raw!A:A)

Spot the Error

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

Question 1

A Open survey_raw.csv

B Rename it to survey_clean.csv

C Clean the copy only

D Keep survey_raw.csv unchanged

Question 2

A data_v1.csv <- original

B Save edits as data_v1.csv

C Never overwrite data_v1.csv

Question 3

A Sheet1 is named Raw

B Sheet2 is named Clean

C Paste values into Raw A1

D Do all edits on Clean

Question 4

A Download results_raw.csv

B Save a backup on cloud drive

C Edit results_raw.csv directly

Question 5

A Clean the data before copying

B Clean only the copy

C Raw data stays unchanged

Answer Key

Keeping an untouched copy of the raw data

Section A: Quick Questions

B — Keep the original data untouched on a Raw sheet and clean a copy

A — A sheet called Raw that is never edited and a sheet called Clean for changes

A — False - keep the Raw sheet in case you need to check or redo the cleaning

A — survey_data_v2.csv

B — Copy the column back from the untouched Raw sheet

Section B: Match the Pairs

=Raw!B2 → Pulls a value from the Raw sheet into the Clean sheet so the original cell stays untouched

survey_data_v2.csv → A file name with a version number, showing this is the second saved version of the data

Keep the original data safe by cleaning only a copy on a separate Clean sheet → Sheets: Raw | Clean

Save a new version of the file before each big cleaning step so you can go back → results_v1.xlsx -> results_v2.xlsx

Delete duplicate rows directly on the Raw sheet → Editing the raw data permanently changes the original, so the deleted rows cannot be recovered

data.csv (saved over the old file after cleaning) → Overwriting the same file name destroys the earlier version, so there is no backup to return to

Section C: Definitions

raw data copy — Keep the original data untouched on its own Raw sheet or file, then clean a copy on a Clean sheet, so any mistake can be undone. Version numbers like data_v2 and backups help.

Section D: Fill in the Blanks

=TRIM(Raw!A2)

Raw: survey-v1.csv, Copy: survey-v2.csv

=PROPER(Raw!B2)

=UPPER(Raw!A2)

=COUNTA(Clean!A:A)=COUNTA(Raw!A:A)

Section E: Spot the Error

B — Renaming the file means the original raw file no longer exists. You must copy it to survey_clean.csv so the raw file stays untouched.

B — Saving the edits as data_v1.csv overwrites the original file. Edits should be saved under a new version number such as data_v2.csv.

C — The copied data must be pasted into the Clean sheet. Pasting into Raw overwrites the original data and defeats the purpose of the Raw sheet.

C — Editing the raw file directly risks losing the original data. All cleaning should be done on the copy, results_clean.csv.

A — The copy must be made first. If you clean before copying, the original raw data has already been changed and can't be recovered.