Repair the comparison
Subtraction does not fix a confound
Same 20 minutes in a 22°C room; cups, lids and method match. Sleeve and mass differ.
Equal starts, unequal masses
Constructed teaching data: these values were invented for this activity, not collected in an experiment.
Setup | Mass (g) | Start (°C) | Final (°C) |
|---|---|---|---|
Sleeve H | 60 | 10 | 17 |
Sleeve J | 120 | 10 | 15 |
1. Find both changes. Can the lower increase isolate a sleeve effect? Repair the comparison.
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Fresh check
New equal samples in a 23°C room, same cups/lids, method and 15-minute exposure. This is one matched trial.
A matched comparison
Constructed teaching data: these values were invented for this activity, not collected in an experiment.
Setup | Mass (g) | Start (°C) | Final (°C) |
|---|---|---|---|
Sleeve U | 100 | 12 | 17 |
Sleeve V | 100 | 12 | 16 |
2. What bounded sleeve comparison is supported? What is not established?
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