Notes Measurements Describing Data
Measurement: a type of observation, a form of data Words You Need to Know… Measurement: a type of observation, a form of data
Words You Need to Know… Measurement: a type of observation, a form of data Qualitative Data: descriptive observation Ex: hot, cold, heavy, light, big, blue, furry
Words You Need to Know… Measurement: a type of observation, a form of data Qualitative Data: descriptive observation Ex: hot, cold, heavy, light, big, blue, furry Quantitative Data: numerical observation that includes both a number; measured Ex: 12 in, 13.5°C, 25kg, 17L
Uncertainty There is uncertainty in all measurements, which is a range of possible values within the range of where the true value lies. + / - half of the smallest measurement
Uncertainty There is uncertainty in all measurements, which is a range of possible values within the range of where the true value lies. ± half of the smallest measurement
Well, what about the certain digits? The “certain” digits include all numbers read directly off of the measuring device PLUS one extra estimated digit. Ex: This device is a graduated cylinder. The units are mL. The proper reading should be:
Accuracy v. Precision Accuracy: How close a measurement is to the true or accepted value Precision: How close multiple measurements are to each other Ex: Weighing a 50g mass Accurate/Precise? Accurate/Precise? 50.00g 32.18g 49.99g 32.18g 50.00g 32.18g
An easy way to remember… ACcurate = Correct PRecision = Reproducibility