Presentation on theme: "Accuracy: The closeness of a measurement to the true or actual value"— Presentation transcript:
1 Accuracy: The closeness of a measurement to the true or actual value Accuracy: The closeness of a measurement to the true or actual value. of what is being measured. BEING RIGHT!Accurate: Your measurement = 30.5 cm Actual length = 30.5
2 Precision: how SPECIFIC a measurement is Less Precise More Precise10 m m m 12 m m m9 m m mGroups of measurements that are CLOSE in range to each other = more preciseMore SIG. FIGS. = more precise
4 Precision Which ruler is the most precise? Which ruler is not accurate?
5 PrecisionPrecision of calculated answers is limited by the least precise measurement.Ex: 2.5 cm cm = 4.75 4.8Measurements can be precise, but not accurate if an instrument is not calibrated correctly.
6 Precision & Significant Figures Answers cannot be more precise than the least precise information givenExamples= 23.72Answer: 23.7In + and - : Keep same # of decimal places
7 Answers that Reflect Precision ADDING OR SUBTRACTING: Answer can only show as many decimal places as the measurement having the fewest number of decimal places.Example: When we add 3.76 g g g = gOur final answer is 20.7 g
8 Practice Quizzes on accuracy & precision: Key Points:Accuracy – Are your measurements close to the true value?Precision – Are a group of measurements close to each other or in agreement?More precise instrumentation leads to greater precision.