1. Notes
Measurements
Describing Data

2. Measurement: a type of observation, a form of data
Words You Need to Know…
Measurement: a type of observation, a form of data

3. 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

4. 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

5. 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

6. 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

7. 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:

8. 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 g
49.99g g
50.00g g

9. An easy way to remember…
ACcurate = Correct PRecision = Reproducibility