Meeting 2: live coding

Work in materials/live-starter/ using the root launch page. The starter runs at its first checkpoint. Keep one browser tab and the Console open; save and refresh after each change. Your instructor will release the reference solution after an attempt.

L1. Four arithmetic items (15 min)

Use all ARITHMETIC_ITEMS in the procedure and set randomize_order to true. Explain how the stimulus function gets the current item.

Success: Four distinct IDs and correct visible arithmetic.

Hint (after an attempt): Use evaluateTimelineVariable inside the stimulus function; direct data properties can use timelineVariable.

L2. Score responses (10 min)

Replace the null correctness placeholder with a guarded comparison of response and expected key. Test correct, wrong, and no response.

Success: Booleans are correct and the omission has correct=false.

Hint (after an attempt): Guard response===null before compareKeys.

L3. End summary (10 min)

Add the supplied summary to the timeline; trace its task/block and RT filters.

Success: Summary is computed after responses and N/A appears if no eligible RT exists.

Hint (after an attempt): The summary stimulus is a function. Course.summarize uses correct finite RTs.

Before moving on

Explain one changed line to a partner and inspect the relevant saved row. Record the first unresolved error rather than copying an entire replacement script.

Download this meeting’s starter files, or use the matching folder in the whole student course download.

A small example before the full task

Use the predict–run–explain practice sheet and the editable examples in the browser slides. Each isolates one idea, shows the resulting data, and includes an independent transfer question.