1. What are Error Intervals?
Error intervals are the limits of accuracy when a number has been rounded or truncated. In other words, they represent the range of values that a number may have taken had it not been rounded off or truncated.
2. What are Truncated Values?
When a number has been truncated it has been cut off. If we truncate a number to one decimal place we delete all digits after one decimal place. If we truncate a number to two decimal places we delete all digits after two decimal places.
Example: Truncate 19.68923 to two decimal places
Solution:
3. How to find error intervals?
In order to find the error interval of a rounded or truncated number, we follow these steps:
- Identify the place value of the degree of accuracy stated.
- Here, we consider two cases:
Case A: If rounded
Divide this place value by 2, and then add and subtract this amount to the given value to give the maximum and minimum values for your error interval.
Case B: If truncated
Add the place value to the given value. This will be the maximum value of your error interval, the given value will be your minimum.
3. Write your error interval as an inequality in the form
Minimum Value ≤ x < Maximum Value
Example: A number x has been rounded to one decimal place The result is 2.8. Write down the error interval for x.
Solution:
Example: Kasim travels 430 km, correct to the nearest 10 km. His average speed is 57.3 km/h, correct to 1 decimal place.
Calculate the shortest possible time for Jamal's journey. Give your answer correct to the nearest minute.
Solution:
