# ﻿Error Intervals

Warmup

Activity #1

How to Measure Angles.

A saw mill cuts boards that are 16 ft long. After they are cut, the boards are inspected and rejected if the length has a percent error of 1.5% or more.

(1.) List some board lengths that should be accepted.

(2.) List some board lengths that should be rejected.

(3.) The saw mill also cuts boards that are 10, 12, and 14 feet long. An inspector rejects a board that was 2.3 inches too long. What was the intended length of the board?

Activity #2

Exercises on Error Intervals.

The reading on a car’s speedometer has 1.6% maximum error. The speed limit on a road is 65 miles per hour.

(1.) The speedometer reads 64 miles per hour. Is it possible that the car is going over the speed limit?

(2.) The speedometer reads 66 miles per hour. Is the car definitely going over the speed limit?

Activity #3

More Exercises on Error Intervals.

Jada measured the height of a plant in a science experiment and finds that, to the nearest of an inch, it is inches.

(1.) What is the largest the actual height of the plant could be?

(2.) What is the smallest the actual height of the plant could be?

(3.) How large could the percent error in Jada’s measurement be?

Challenge #1

An industrial scale is guaranteed by the manufacturer to have a percent error of no more than 1%.

Challenge #2

The mass of a pencil is 58 grams to the nearest gram. Complete the error interval for the mass of the letter.

Challenge #3

Frank rounds a number, n, to the nearest ten. His result is 80. Write down the error interval for n.