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STATISTICAL ANALYSIS OF DATA
STATISTICAL ANALYSIS OF DATA
Calibration of a 10 mL pipet
Calibration of a 10 mL pipet
Learning Objectives
Learning Objectives
The student at the end of this experiment will be able to
(CLO2). Apply the methods of scientific inquiry
(CLO3). Analyze evidence to decide if generalizations or conclusions based on the obtained data are warranted
(CLO4). Interpret and utilize mathematical formulas while solving problems
(CHM 111 MLO1) Apply units of mass, temperature, time, length, and derived units, such as volume and density using dimensional analysis to solve problems with single or multiple steps or conversions.
(CHM 111 MLO1) Evaluate the uncertainty, accuracy, and precision of measurements.
Apply statistical analysis to determine the validity of each data in a set
use a volumetric pipet properly to measure volume and evaluate the precision and accuracy of the volumetric pipet
Define calibration and explain why a pipet calibration is performed
Experiment 20 discusses the precision and accuracy of data. How good is the data collected?
You will need to complete the following assignments
The pre writing assignment and collection of laboratory data
a laboratory report with the data, results, calculations and graphs required for the report
Discussion
Discussion
The calibration of a pipet requires mastery of two of the most common operations in the laboratory: measurement of mass (weighing) and the measurement of volume of a liquid. The calibration of a 10-mL transfer pipet requires multiple measurements. Each measurement is unique and most likely different due to the errors associated with most measurements. The spread or range between the highest and lowest will depend on how carefully the measurements are performed during the calibration.
We will attempt to answer several questions throughout the course when collecting data in the laboratory:
How reliable are these measurements?
Does any value differ so widely from the others that it should be discarded? Should any outlying value be discarded?
What is the "best" value that can be derived from the values, the average or the median?
Leading to the final questions:
What is the precision of the measurements, i.e., how closely do they agree among themselves? and
What is the accuracy of the average or median, i.e., its closeness to the true value?
The full discussion is present in the document.
Accuracy and Precision for Data Collection
Accuracy and Precision for Data Collection
Professor Dave Explains - In science, we love data! But what are the rules of data collection? How accurate and how precise can we get with our data? What do these words even mean? Let's find out!
dixon_q_test.pdfPre laboratory Writing Assignment
Pre laboratory Writing Assignment
Complete the pre laboratory writing assignment in your laboratory notebook. The prewriting must be completed before the laboratory session begins. The writing should include a purpose/hypothesis of the experiment, a discussion or theory, a detailed step by step summary of the procedure explaining what data will be collected and how you will collect it. Data Tables or space to collect the data should be included within the procedure discussion. Look up any SDS on chemicals that you are not familiar.
There are no pre laboratory problems for this assignment.
Procedure and Report
Procedure and Report
We will collect the mass of 2 - 4 trials of 5 aliquots of pipetted deionized water. Using density of the water at the measured temperature, the volume of each aliquot will be determined. Calculate the volume of each aliquot of water from the mass and the reported density. The density of water is approximately 1 g/mL but density changes with temperature. The reported density of water at specific temperatures can be found in the Table of Density of Pure water at temperatures from 0 degree Celsius to 30.9 degree Celsius given in the laboratory assignment, Appendix M: Physical Properties of H2O or using an online calculator.
https://www.simetric.co.uk/si_water.htm#tap
Water density Calculator: https://antoine.frostburg.edu/chem/senese/javascript/water-density.html\
The following spreadsheet can be used to calculate your results.
NAIT Chemical Technology
This video shows how to pipet a liquid using a volumetric pipette.
Complete the assignment by performing statistical analysis and a Q test of the data.
Complete the assignment by performing statistical analysis and a Q test of the data.
https://sisu.ut.ee/measurement/frequently-asked-questions
This link discusses the analysis of data including uncertainty and estimation of errors.
https://youtu.be/K3zxIJm0v70
Dixon Q Test for Outliers
Dixon Q Test for Outliers
MathsResource.github.io | Dixon Test for Outliers
This video shows how to complete a Q test on outliers, the following video shows how to complete the calculation of Q in an Excel spreadsheet.
How to Perform a Q Test to Find Outliers in Excel 2016
How to Perform a Q Test to Find Outliers in Excel 2016
Excel, Word and PowerPoint Tutorials from Howtech
In this HowTech written tutorial, we’re going to show you how to perform a Q test to find outliers in Excel 2016. Don't forget to check out our main channel https://www.youtube.com/c/HowTech for more free how-to videos! Join us on Facebook http://www.Facebook.com/howtechtv Our App http://bit.ly/how-tech The measurements or values must first be in ascending order according to which possible outlier to test. To calculate gap, use the formula given in the screenshot. Calculating the range of the data is fairly simple as shown. Calculating Q is even simpler. Just divide the gap by the range. You will need a confidence interval and critical value, this table can be looked up online. Finally, I created a quick IF statement to check to see whether or not the value is an outlier or not. If the Q is less than the critical value, it is not an outlier. If it is greater than, it is an outlier. This is a HowTech tutorial, visit our website and watch our videos for more.
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