Measurement Precision Accuracy Measurements need to be precise and accurate!

Accuracy How close a measurement comes to the true or accepted value (target). Ex: If you make the extra point after a td, you are an accurate kicker. Ex: Your weight at the Dr is 125 lbs. Your scale at home shows 125 lbs also. Your home scale is accurate. To determine the level of accuracy, you can compare your measurement to the target measurement.

Precision How close multiple measurements of the same quantity are to each other. EEx: An archer misses the target three times in a row, but all her arrows land near the same spot on the ground. The archer is precise (but not accurate). EEx: is more precise than 3.14.

The level of detail in a measurement How to Determine If measure are in same units, most precise is smaller fraction or more decimal places If measures are in different units, most precise is the smaller unit

Accuracy The closeness of a measured value to the actual or true value How to Determine Subtract measured values from the true value. The smallest difference is the most accurate.

Higher Precision A measuring device with more marks on the scale is more precise. I.e., we are estimating less, and get a more accurate reading. Here we are estimating the hundredths place instead of the tenths. Which measure is most precise? 1 cm 1.25 cm m Hint: the smallest unit of measure OR the more numbers after the decimal place usually means higher precision 1 cm2 cm3 cm ABCD

High Accuracy (Darts are all in the center of the Bullseye) High Precision (All the darts are close to each other) Accuracy and Precision

Low Accuracy (All darts are far away from the Bullseye) High Precision (All darts are very close to each other)

Accuracy and Precision Low Accuracy (None of the darts are in the center of the bullseye) Low Precision (None of the darts are close to each other)

Precision and Accuracy Good precision Good Accuracy Good Precision Poor Accuracy Poor Precision Poor Accuracy