Accuracy and Precision Lab Report

Accuracy and Precision Lab Report Introduction In spite of the fact that the terms accuracy and precision are frequently seen as synonymous or as one and the same, they have each an exceptionally distinct definition. Accuracy is how close a measurement or set of measures is to a real value. Precision is how close the value in a set of measurements are to one another. The purpose of this experiment was to analyze the accuracy and precision of beaker, pipette and, graduated cylinder. After the analysis of purpose, we expect hypothesis of experiment; that the pipette was most accurate, and graduated cylinder was most precised one. My hypothesis assumption was convinced from the theory that pipette allows a greater amount of control on how much fluid you want. With a graduated cylinder, you pour the fluid into it, and risk accidentally pouring in too much or not enough, causing you to have to pour some out or add still more. Method and Materials In this experiment, beaker, pipette, graduated cylinder, DI water and measuring balance were the materials that were provided by the instructor. At the beginning, temperature of room was observed before starting the experiment. Measuring balance was used to dispense 10 ml of DI water to determine the mass. At first, we fill 10 ml of water in beaker of 50 ml and the value of mass was calculated with the help of measuring balance. The process was repeated to 4 times for beaker. As for the pipette, we again filled the DI water in beaker and pipette was used to suck 10 ml of water and poured into empty beaker. Same with the help of measuring balance the mass was calculated. This process was same repeated for 4 times for pipette. Afterwards, for graduated cylinder 10 ml of water was poured into graduated cylinder and mass was measured by balance. The process was repeated for 4 times simultaneously. As soon as the measurements was completed, I converted those masses into volume by using the density of water of temperature of room that was observed at very beginning of experiment. The measurements of volumes were used for Q test, I calculated Q high and Q low for all three set of measurements. With the collection of data, I calculated mean and standard deviation to determine the accuracy and precision of given instruments. Data Temperature of water: 23oC Density of water: 0.9975415 g/mL Table 1: Mass of 10 ml water dispensed using beaker Trial s Actual Vol. Targeted Vol.(Ml) Measured Mass (g) (mL) 1 10 9.704 g 9.727 2 10 10.432 10.457 3 10 9.672 9.695 4 10 9.784 9.808 5 10 9.432 9.455 QH = 0.648 QL = 0.352 Result and Conclusion Mean Volume = 9.8048ml SD = 0.374 ml As the purpose of this experiment was to analyze the accuracy and precision of beaker, pipette and, graduated cylinder. The above data collected was used to determine the accuracy and precision of the instruments. To find the accuracy mean values of each tools were observed following the theory that more the mean value, more accurate it is. Taking an eye on the theory and interpretation of data concludes that beaker was more accurate as its mean was closest to 10 ml (9.8048). In other hand, to find the precision value SD values of each tool were observed following the theory that the precision increases as the standard deviation value decrease, meaning the lower the number the more precise the value and vice versa. Based on data, pipette was more precised one as its SD was lowest in comparison to others(0.184ml). My original hypothesis was the pipette was most accurate, and graduated cylinder was most precised one. Analysis of all the data above shows validation of hypothesis of accuracy. In contrast the hypothesis of graduated cylinder being more precised was invalid as its standard deviation value was not lowest in comparison to beaker and pipette. On a total basis, my hypothesis regarding precision was rejected.