Glassware Stock Sheet with Two Hidden Errors
At 4:30 p.m. you are preparing the monthly glassware stock sheet in the laboratory computer. The file “Glassware_Stock_April.xlsx” is open. Cell F12 uses =SUM(F2:F11) and shows 43 beakers. Your manual count on the shelf is 42. You notice that cell F7 contains 12, but the shelf label for that row says 6; cell F9 contains the letter “S” where 5 should be. The sheet is shared with the store officer, and the original file has no backup. A pen drive labelled “backup” is on the desk, but it contains an older copy from March. The store officer will check the sheet at 5:00 p.m. and wants a short email with the corrected total. Explain what you would do, in order, and what you would write.
1. Explain why the sheet shows 43 instead of 42 and state exactly what should be corrected.
Read the worked answer
F7 is overstated by 6 (12 instead of 6). F9 is text “S,” so SUM ignores the 5 that should be there. The net error is +6 − 5 = +1, which is why the sheet shows 43 instead of 42.
Correct F7 to 6 and F9 to 5, then recheck the total. Do not simply type 42 into F12; fix the source cells so the formula remains trustworthy.
2. What file-handling steps would you take before editing, and what should the email to the store officer contain?
Read the worked answer
Before editing, use Save As to create a copy named with today’s date, for example Glassware_Stock_April_corrected.xlsx; keep the original unchanged. Do not use the March pen-drive copy as the current file because it is out of date.
Edit the copy, correct F7 and F9, verify the total against a fresh manual count, and save. Then email the store officer with the subject “Glassware stock April - corrected total 42.” State the file name, the two corrections, and the time. Attach the corrected copy or give its location.
3. How would you prevent this kind of error in next month’s sheet?
Read the worked answer
Lock the total formula and protect the sheet, or use data validation to allow only whole numbers in count cells. Add a manual-count column and a check cell that flags any difference, so text entries are caught. At month end, save a dated backup before editing.
These steps prevent a single text entry or a wrong range from silently changing the total.