Two slow times stay in the published list

Lesson map

Lesson 15. Map, example, EX061.

flowchart TD
  L["Times include 95 and 110"] --> O["over 60 s: 2"]
  O --> M["Median of the full list: 40 s"]
  F["Ruth later adds the report address to the phones"] --> N["That fix is after the list"]
  N --> R{"Does someone drop 95 and 110?"}
  R -->|Yes| X["Refuse. This lesson does not rerun the median"]

A fix found after the test does not delete the times that revealed the problem.

Logical drawing

published times
    25, 31, 34, 38, 42, 47, 95, 110
published summary
    correct 7/8
    median time 40 s
    over 60 s: 2
later fix
    report address added as a contact on shared phones
        |
        +-- the contact was not on the phones during these eight times
        +-- 95 and 110 stay
        +-- the median is not recomputed here

Learning outcomes

After this chapter, you should be able to:

1. Keep 95 and 110 inside the published time list.
2. Keep the median at 40 seconds for that full list.
3. Place the phone-contact fix after the test, not inside it.

15.1 The slow pair is why the phones were changed. It is not a pair to erase.

Two of the eight times are over a minute: 95 seconds and 110 seconds. The print says over 60 s: 2, and the median of the full sorted list is 40 seconds. Ruth then adds the report address as a contact on the shared volunteer phones, because people struggled to find it. A classmate deletes 95 and 110, saying the phones are fixed so those times no longer count, and asks for a new median. The contact was added after the eight attempts. Removing the pair would be a different list, and this lesson does not run that list. The published median stays 40 seconds.

15.2 Worked example

Lesson table; scroll horizontally to read all columns →

Synthetic case. No new median is calculated. The eight times stay the ones in the program.

Errors and limits

Keeping the slow times does not mean the phone contact was pointless. It means the contact does not rewrite the afternoon that prompted it.

Apply

• EX061 — Which times stay? The published list includes 95 and 110, the median is 40 seconds, and two times are over 60 seconds. Ruth adds the report address to the phones afterwards. A teammate drops the two slow times. What stays, and what do you not recompute?
  Show marking criteria

  Rubric: 3 = 95 and 110 stay; the median stays 40 seconds for the full list; the phone contact is after the test; do not recompute; do not edit the script;; 2 = the slow times stay and the median is not redone;; 1 = one of those;; 0 = none.