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Bell Ringer. Percent Change. Mr. Haupt CC.2.1.8.A.2; CC.2.1.8.A.3. Changing the Percents and Stuff. Percent of change simply tells us the ratio that something goes up or down. Very easy equation. You just take the difference in the two numbers, and divide by the original number.
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Percent Change Mr. Haupt CC.2.1.8.A.2; CC.2.1.8.A.3
Changing the Percents and Stuff • Percent of change simply tells us the ratio that something goes up or down. • Very easy equation. You just take the difference in the two numbers, and divide by the original number. • Percent change = amount of change original amount • When a value increases from the original, it is a percent of increase, when it decreases from the original, it is a percent of decrease.
Examples • Find the percent change: • $2 to $3 • 9 m to 12 m • $38 to $65 • 125 lb to 143 lb
Greatest Possible Error • Since no measurement is exact, we always round to the nearest “something.” • The greatest possible error in a measurement is one half of that measuring unit. • If you are using a balance beam to find the mass of a rock sample in science class, and you read the scale as 3.8 g, what is the greatest possible error? Since you measured to the nearest 0.1 gram, your gpe is 0.05 g.
Examples • What is the greatest possible error? • 14 ft • 3.5 cm • 56.38 g • 17 in
Percent Error • Percent error is another way to think of error in a measurement. • It is found using the ration of the greatest possible error and the measurement. • percent error = greatest possible error measurement • If you measure a CD and it has a diameter of 12.1 cm, what is the percent error in your measurement?
Examples • Find the percent error: • 2 cm • 4 cm • 19.7 in • 123.45 m