1. Physics 2215 Minilab 1: Measurement and Estimation Purpose Gain experience in calculating and propagating errors associated with measurements. Gain experience in performing rough estimations.

2. Physics 2215 Minilab 1: Measurement and Estimation Finding Uncertainties from Repeated Measurements Repeated measurements can give you different results due to Object variation (e.g., the width of a table may be different at different positions, or it may vary with temperature or moisture in the air). Measurement device or procedure may create scatter in the result.  Take many (5 or more) measurements and calculate the mean.

3. Physics 2215 Minilab 1: Measurement and Estimation Mean Standard Deviation Standard Deviation of the Mean This is the uncertainty/error in the mean value. A measure of how far individual data scatter. Result

4. Physics 2215 Minilab 1: Measurement and Estimation Error Propagation A general physics formula…..And some measurement with uncertainties….. Plug in x, y, z….. to get value of “ f ” Calculate uncertainty in “ f “: Result

5. Physics 2215 Minilab 1: Measurement and Estimation Estimations…an example How many (NT) new car tires are bought in Utah every year? P: Population: 2 Million A: % that are adults and drive a car: 60% M: Number of miles driven per adult per year: 15000 miles N: Number of tires per car: 4 L: Number of miles during life of tire: 45000 miles

6. Physics 2215 Minilab 1: Measurement and Estimation What we will look at closely when grading…  Did you make reasonable estimations/calculations of uncertainties?  Did you report significant figures correctly?  Did you propagate your errors without mistakes?  When you performed an estimation, did you perform logical reasoning to arrive at your estimate.