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Week 05 Β· Storing Data

Friday

Impact Friday: Keep or let go?
// From answers to codes to bits
⏱ about 20 min

Friday: Impact Friday: Keep or Let Go?

Comet has a new idea. "When the report is done, let's put the whole data sheet online! Then everyone can see our work."

Wren pulls out the privacy checklist from week 3. "The whole sheet? Every row, with every open-box answer?"

"Sure," Comet says. "There are no names on it."

"What do you notice about the open boxes, though?" Wren asks. "Some members wrote details about their own visits."

Comet reads a few and goes quiet.

Nova hovers over the checklist. "Would you like a hint?" she asks. "Ask what the data were collected for, and what they need to do after the report."

Keeper Ines nods. "The council asked one question. Maybe the sheet only needs to answer that one."

Data can outlive its purpose

Information placed online can be used in ways that were not intended. Once it is online, it is difficult to delete.

Scattered bits of data can be combined to learn about one person. You learned this in week 3.

Where data are stored affects privacy and integrity, and encryption and passwords help block unauthorized access.

So the crew plans what happens to each part of the data once the report is done.

Part of the dataThe crew's plan after the report
Totals for each questionKeep and share with the council
Code bookKeep with the totals so they can be read
The 40 coded rowsKeep on the password-protected computer until the report is final, then delete
Raw paper forms and printed sheetsKeep locked away until the report is final, then shred
Q6 open-box answersNever post; summarize for the council without quoting details

This plan is part of the Commons Count story.

KEEP OR LET GO?
  • Read the question.
  • Tap your answer.
What does the crew share with the council?
Why keep the code book with the totals?
Why not post the whole sheet online?
StatementTrue or false?
Information placed online is easy to delete later.?
Data can be used in ways that were not intended.?
Removing names means no other detail could point to a person.?
Deciding what to keep and what to delete is part of storing data well.?
WHY THIS EXERCISEGood storage includes a plan for the end, not only the start.

Week review

  1. A code book turns answers into numbers. The same code can mean different things in different columns.
  2. Bits are 0 or 1, and a byte is 8 bits.
  3. In binary, place values are 1, 2, 4 and so on. Two bits hold four codes; code 4 needs a third bit.
  4. A fixed number of bits limits the range, which can cause an overflow error.
  5. Lossless compression rebuilds exactly. Lossy compression rebuilds only an approximation.
  6. Where data live affects speed, reliability, accessibility, privacy and integrity.
ORDER THIS WEEK'S STORAGE STEPS
  • Tap a card.
  • Then tap its spot.
1First
2Next
3Then
4Last
WEEK CHECK
  • Read the question.
  • Tap your answer.
What is code 4 in binary?
Which compression lets you rebuild the original exactly?
On paper, sketch a simple timeline for the Commons Count data: collected, coded, reported, then kept or deleted.

What a week, data analyst. Tomorrow is Mission Quest: a family code book and paper bit cards.

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