Lecture1Errors in MeasurementsFall23handout

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8/25/2023 1 1-1 Uncertainties in Analytical Measurements 8/25/2023 2 1-2 ACCURACY & PRECISION Treatment of Data:
8/25/2023 3 1-3 Reliability of Data ๏‚ง Precision - reproducibility of results - represented by the standard deviation & variation ๏‚ง Accuracy - correctness of result - expressed as relative or absolute error (E a ) ๐‘ฌ ๐’‚ เตŒ ๐’™ฬ„ เต† ๐’™ ๐’• ๐ซ๐ž๐ฅ๐š๐ญ๐ข๐ฏ๐ž ๐ž๐ซ๐ซ๐จ๐ซ เตŒ ๐’™ฬ„ เต† ๐’™ ๐’• ๐’™ ๐’• เตˆ ๐Ÿ๐ŸŽ๐ŸŽ % 8/25/2023 4 1-4 Measurement Precision The Tale of Two Balances: - Balance 1: ยฑ 0.1 g Measurements Precision 12.3 0.813 % 12.4 0.806 % - Balance 2: ยฑ 0.0001 g Measurement s Precision 12.3115 0.00081225 % 12.3667 0.00080862 %
8/25/2023 5 1-5 Precision & Accuracy โ€ข Speed of light (3 ร— 10 8 m/s) measurements: Measurements Precision Accuracy (2.5005 ยฑ 0.0002) ร— 10 8 m/s 0.008 % low (2.50 ยฑ 0.08) ร— 10 8 m/s 30 % high โ€ข Why do you think it's important to keep the correct number of significant figures when reporting measurements? โ€ข Why can't measurements be always precise & accurate? 8/25/2023 6 1-6 ERRORS & UNCERTAINTIES Treatment of Data:
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