Worked examples
Two examples
Example 1
Height of a tomato plant
Made-up numbers, for practice.
No one measured the plant on day 25. What is the best estimate of its height that day?| Day | Height (cm) |
|---|---|
| 0 | 4 |
| 10 | 24 |
| 20 | 44 |
| 30 | 64 |
| 40 | 84 |
- Day 25 is between two measured days, 20 and 30. Estimating between measured points is called interpolation.
- On day 20 the plant was 44 cm; on day 30 it was 64 cm.
- Day 25 is halfway between day 20 and day 30, so the height was about halfway between 44 and 64.
- Halfway between 44 and 64: (44 + 64) ÷ 2 = 54.
- This estimate is fairly safe, because there are measurements on both sides of it.
Answer: About 54 cm
Example 2
Temperature of a cup of coffee left on a table in a 22 °C room
Made-up numbers, for practice.
Continue the pattern of the last rows straight ahead, and you might guess the coffee will be about 10 °C after two hours. Is that a safe estimate?| Minutes | Temperature (°C) |
|---|---|
| 0 | 80 |
| 10 | 50 |
| 20 | 36 |
| 30 | 28 |
| 40 | 25 |
- Two hours is 120 minutes, far beyond the last measurement at 40 minutes. Estimating beyond the measured points is called extrapolation.
- Extrapolation is a guess: the pattern may change where no one measured.
- Here it does. Coffee on a table cannot get colder than the room, 22 °C. The cooling slows down and levels off near 22.
- So the coffee will be about 22 °C, not 10.
Answer: No. It will level off near room temperature, 22 °C.
Where this is taught: Science Practices, part 4: Tables and graphs · Look Again Quiz 3: Tables and Graphs
In your Kaplan book: Unit 4, Chapter 1, Lesson 4: Express and Apply Scientific Information · Map of the Terrain, topic 3: Tables and graphs
The drill
Ten questions
How many:
Read what is in the box first, if there is one. Then tap your answer; a few questions ask you to choose words from a drop-down instead, the way the GED test does. Press Check my answers at the bottom.Read what is in the box first, if there is one. Circle your answer; where there are brackets, circle the choice that fits. The answer key, with the reasoning, is on the last page.