JentooACT®

ACT® · Science: Scientific Investigation (6-11 items)

Predicting the Result of an Additional Trial (SIN 502)

You predict an untested trial by reading the trend in the data you already have, then extending it to the new value or filling in the gap between two measured points.

A table of trials is just a record of what happened at certain settings. If those results move in a steady pattern, like doubling every 10 degrees or rising by a fixed amount each step, that pattern almost always holds for settings nobody tested yet. So you're not guessing. You're reading the rule the data already wrote and applying it one more time.

To predict a trial past the end of the table, find the step size, then count how many steps separate the new setting from the last one tested and apply the pattern that many times. If the new trial falls between two rows instead of past them, you don't need the step size at all. Just use the two surrounding values as a floor and ceiling: a steady trend can't jump outside its own neighbors.

The one twist sits at the far edge of the table. A line fitted to four or five trials only describes the range it was built from. Push the prediction far past that range and you're trusting the pattern to hold somewhere it was never checked, which is risky if the setup has a built-in ceiling or breaking point, like an enzyme that denatures past a certain temperature. This is where the skill connects to reading experimental limits elsewhere in the unit: a good prediction always asks not just what the trend says, but whether anything in the setup would stop the trend from continuing.

Key terms

Trend
The steady pattern a set of trial results follows, such as a constant increase or a constant doubling.
Interpolation
Predicting a result for a setting that falls between two settings already tested.
Extrapolation
Predicting a result for a setting that falls beyond the range of settings already tested.
Tested range
The span of settings for which actual trial data exists.

Watch it explained

  1. How it worksHow do you extend the pattern in a trial table by one row and read the predicted result off the end?
  2. How it worksWalk me through predicting a trial that falls between two existing trials instead of past them.
  3. Worked exampleFind the predicted yield at 60 C when trials at 20, 30, 40 and 50 C gave 2, 4, 8 and 16 grams.
  4. Going furtherWhat happens to a prediction when the trial being asked about sits far outside the range that was tested?

Check yourself

Your turnmedium1 of 3
Table 1 lists yields at 20, 30, 40 and 50 degrees C. The 20 degrees C trial gave 5 g, and each 10 degree step doubled the yield. What yield, in g, does the pattern predict for an additional trial at 60 degrees C?

End of topic.