Error sources Random errors Odometer readout resolution Odometer mechanical variations Route path variations ire Slippage Systematic errors Bias in the odometer readings Odometer scale factor error Tire diameter decreases due to wear
Error Sources Random errors Odometer readout resolution Odometer mechanical variations Route path variations Tire slippage Systematic errors Bias in the odometer readings Odometer scale factor error Tire diameter decreases due to wear
Error Sources(cont The resolution I achieved in reading the odometer was within t 025 miles The best knowledge I have about the other random errors is that they were all in the range of±.10 miles i zeroed the odometer at the beginning of each trip so any bias in the measurements is small (i. e about t.005 miles)
Error Sources (cont.) • The resolution I achieved in reading the odometer was within ±.025 miles • The best knowledge I have about the other random errors is that they were all in the range of ±.10 miles • I zeroed the odometer at the beginning of each trip so any bias in the measurements is small (i.e. about ± .005 miles)
Error Sources(cont) I did a scale factor calibration by driving 28 miles. according to mileage markers on Interstate 95. and in both directions i recorded 27. 425 miles on my odometer Thus the scale factor is 27425 odometer indicted miles SF 980 28 actual miles And any error in the scale factor due to readout resolution is 025 SE ×9 ±0006
Error Sources (cont.) • I did a scale factor calibration by driving 28 miles, according to mileage markers on Interstate 95, and in both directions I recorded 27.425 miles on my odometer • Thus, the scale factor is 27.425 odometer indicted miles S.F. = = .980 28 actual miles • And any error in the scale factor due to readout resolution is .025 e ≅ ±.0006 SF = ± 28⋅ 2
Recorded data Trip Mileage S.F. Corrected Number Reading Mileage reading 7.8257.985 7.8508.010 7.8758.036 79008061 78508010 7.8257985 7.8758036 7.8508.010 78758036 10 78257985
Recorded Data Trip Number Mileage Reading S.F. Corrected Mileage reading 1 7.825 7.985 2 7.850 8.010 3 7.875 8.036 4 7.900 8.061 5 7.850 8.010 6 7.825 7.985 7 7.875 8.036 8 7.850 8.010 9 7.875 8.036 10 7.825 7.985
Mileage Data Analysis My system model is that the route distance Is constant To minimize the effect of random errors take the sample mean(average)of the data to obtain an estimate d=8.015 miles
Mileage Data Analysis • My system model is that the route distance is constant • To minimize the effect of random errors take the sample mean (average) of the data to obtain an estimate n dˆ = 1 ∑ di = 8.015 miles n i =1