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Grade 8 · unit review

Review: Interpret Data Summaries and Privacy Tradeoffs

For values[1,2,9], calculate the mean and compare it with the median. Then assess a claim that deleting names from detailed unique rows guarantees anonymity.

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Use these 4 new cases to check your reasoning. Choices are temporary and are not saved to an account, sent to staff or recorded as school grades. Download your current review choices before leaving or reloading.

Unit review questions
1. Paper Python 3 expression: sum([5,7,9,11])/len([5,7,9,11]). What value results?
Need a hint?
  • Add the values and divide by the number of supplied values.
  • The mean need not equal a value that any item actually has.
2. Paper Python 3 expression: sorted([7,1,11,5,9])[2]. What value results?
Need a hint?
  • Sort the five values and select index 2 as the middle value.
  • Do not select the third item from an unsorted original list.
3. Direct names removed but detailed attributes remain. Which conclusion fits the stated transformation?
Need a hint?
  • Separate the changed data representation from an unsupported anonymity claim.
  • Name removal alone does not establish that reidentification is impossible.
4. Old results compared with a later period. Which limit is present in the record?
Need a hint?
  • Check the source group, time and measure before generalizing or comparing.
  • More decimal places do not repair biased sampling or incompatible definitions.

The download contains your current choices and any checked feedback. Keep the separate transfer-task work in your own document; downloading its instructions does not mark it complete.

Use the skills in a new task

For values[1,2,9], calculate the mean and compare it with the median. Then assess a claim that deleting names from detailed unique rows guarantees anonymity.

Work on paper or in your own document. Explain the choices you made.

  • Use only supplied fictional inputs and state the relevant rule.
  • Include labeled steps or evidence for each decision.
  • Name one limitation or tempting mistake.
  • Check that the result meets the task and revise a justified error.
Compare with a model response

The mean is 12/3=4 and the median is 2. The high value 9 affects the mean, so it should not be presented as every observation. Name removal alone does not guarantee anonymity in detailed unique records.

A different response can also meet the criteria. Compare the evidence and reasoning, rather than copying the wording.