PPT-Accuracy and Precision of Measurement

2012 Project Lead The Way Inc Introduction to Engineering Design Recording Measurements A measurement always includes a value A measurement always includes units A measurement always involves . 1 02 03 04 05 06 07 08 09 1 Measured Value of x Fraction of Total Measurements SD 01 SD 02 SD 03 brPage 5br mean standard deviation histogram Figure 3 Mass of Unknown Sample 102 104 106 108 11 112 114 116 118 12 Mass kg of Measurements brPage 6br What’s the Diff?. Accuracy. Accuracy: . How . closely a measurement matches true or actual values. To . be accurate only requires the true value (the . bulls eye. ) and one measurement (one arrow to hit . Chapter 1 Section 2. Accuracy. describes how close a measured value is to the true value of the quantity measured. . . a.k.a. “the right answer”, or the agreed upon answer (“consensus” among scientists). Chapter 1 Section 2. Accuracy. describes how close a measured value is to the true value of the quantity measured. . . a.k.a. “the right answer”, or the agreed upon answer (“consensus” among scientists). Graphing and Sig-figs. This should be review ;). Accuracy. = . how close to the accepted value your measurement is. Precision. = . Reproducibility, your measurement closely matches your other measurements. MASS. Definition: Measure of the amount of matter in an object. Value always stays the same, no matter the location in the universe. Measured by a balance. Units expressed in grams (g), kilograms (kg), and milligrams (mg). Precision. Accuracy. Error Types. Significant Digits. Error Propagation. Error in Measurement.  . "Accuracy" means truth.. "Precision" means detail..  . Accuracy. Accurate: measured value very close to actual value.. Using Significant Figures. S8CS3: . Students will have the computation and estimation skills necessary for analyzing data and following scientific explanations.. S8CS3d:.  Decide what degree of precision is adequate, and round off appropriately.. Accuracy vs. Precision. What is the difference?. Accuracy vs. Precision. Precision . accuracy. Exactness. Divisions on scale. Reproducibility. Uncertainty. Significant digits. Correctness. Calibration. When taking scientific measurements, the goals are to measure . accurately. and with . precision. .. Accuracy. . refers to how close a measured value is to the actual or real . value. Precision. . CONTEXT. There are two . contexts precision . and accuracy apply to: sets of data, and measuring instruments.. In a set of data, those measures give an idea of the spread and “. ballpark. ” of the answer (final measurement).. 1 Accuracy and Precision Notes Chemistry 1 2 Uncertainty in Measurements There is no such thing as a perfect measurement! All measurements have a degree of uncertainty because Instruments have flaws Accuracy of a measurement:. An indication of how close the measurement is to the accepted value. Percentage difference can be calculated to give a quantitative indication of a measurement’s accuracy—the smaller the percentage difference, the greater the . Friday. , September 2. nd. , 2016. Accuracy . vs. Precision –. Accuracy. – how close a measurement is to the actual value. Precision. – how close a group of measurements are to each other.. Look at each target below and decide whether the situation is accurate, precise, both, or neither:.