Analysis of a Digital Pipet

Mechanical micropipets are commonly used to dispense small (μL) volumes of reagents.  A recent “Application Note” [Am. Lab. June 1999] contains the following data for 50 replicate deliveries of a reagent using a 5.0-μL micropipet.

Average volume delivered = 4.967 μL

Standard deviation = 0.0467 μL

(a) Evaluate the pipet’s accuracy at α = 0.01.

(b) The pipet’s manufacturer certifies that it will deliver a volume of 5.0 μL with an accuracy of ±1.0% and a relative standard deviation of ±1.0%.  Based on your answer to the previous question and this additional information, would you keep this pipet or return it to the manufacturer?  Explain.

About the Author

ASDL Contributor

David Harvey

Professor of Chemistry & Biochemistry at DePauw University

David T. Harvey is a Professor Emeritus of Chemistry and Biochemistry at DePauw University in Greencastle, Indiana, where he has been a dedicated faculty member since 1986. Over his nearly four-decade career, Dr…
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