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JChemEd.chem.wisc.edu • Vol. 75 No. 7 July 1998 • Journal of Chemical Education 869

Development of Analytical and Reporting Skillsin Quantitative Analysis

R. J. EiermanDepartment of Chemistry, University of Wisconsin–Eau Claire, Eau Claire, WI 54702

This article is a description of activities carried out inquantitative analysis that have as their goal helping studentsdevelop skills in analyzing numerical results of chemical mea-surements, drawing conclusions from them, and choosingwhat to include in a report. The activities are designed toprovide students guidance with appropriate tools and thento give them the freedom and responsibility to choose whatto do and how to do it. Once the students have been ex-posed to and have practiced with the correct methods for cal-culating results, performing statistical analyses, and drawingconclusions from them, it becomes their job to decide whenand how to apply those methods to their own experimentalresults. It is important that students learn that the decisionsare up to them and that they are accountable for what theydecide to do (and not do) as well as how they do it. Severalaspects of the course (student management teams, coopera-tive group work) are included to help students learn that theyare responsible for their own success and that of the courseas a whole.

The development of skills is aided by having the stu-dents go through a set of stepwise experiences:

1. Students learn the basics of chemical measurementprocedures and methods for data reduction andstatistical analysis. Initial learning is done primarily inthe lecture.

2. Students apply those concepts to self-collected experi-mental data in instructor-defined laboratory write-ups.Feedback is given on how well they carried out thespecific instructions.

3. In subsequent experimental write-ups students decidewhat to report and how to report it, given generalinstructions and the identity of the audience for whomthe report is written. Feedback is given on what theydid and didn’t do and how successfully they did it.

4. Finally, students choose, design and carry out a specialproject. They decide what data reduction and statisticalanalysis to do and report their results and conclusionsto other students, the instructor, and other facultymembers in a poster session

An Overview of the Quantitative Analysis Course

Quantitative Analysis (Chem 213) is a 5-credit coursewith lecture (3 hours/week) and laboratory (6 hours/week)taken by second-semester freshmen, sophomores, juniors, andsome seniors after completion of general chemistry and insome cases organic chemistry. The course has dual goals ofhelping students learn the fundamentals of chemical analysis andto review some basic chemical concepts (equilibrium, acid–base chemistry, and electrochemistry) within that context.

Basic statistical methods are taught (confidence interval,comparison of means, screening bad data, linear regression,and propagation of error) and there is a roughly equal splitbetween traditional wet chemical methods (gravimetric andacid/base and EDTA titrations) and instrumental methods(molecular and atomic absorption spectrometry and poten-tiometry). A typical class consists of 56 students split intotwo 28-student lab sections. About 150 students take thecourse each year. The lecture and lab are usually taught bythe same faculty member.

The laboratory consists of a fairly typical set of analyses(see Table 1). Procedures for the analyses are provided in anin-house laboratory manual. The procedures have been writtenin a format that follows the Association of Official AnalyticalChemists (AOAC) standard method format (1). Studentscarry out the procedures working alone or in structuredgroups, analyzing samples that are provided or that they collectthemselves. They work through the experiments at their ownpace. Write-up instructions are provided as the first studentsbegin an experiment; often, lab lectures on the chemistry anddetails of the methods are provided after all students havebegun working on an experiment. Lab reports are collecteda week after everyone finishes the experiment and are gradedby the instructor.

Course ElementsIn this section the activities that are done to carry out

the experiences described above are explained. The item num-bers correspond to the steps described earlier.

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870 Journal of Chemical Education • Vol. 75 No. 7 July 1998 • JChemEd.chem.wisc.edu

1. The Basics of Chemical Measurements andData Analysis

The first several weeks of lecture are spent addressingbasic wet chemical and instrumental analysis strategies,methods for identifying and quantifying experimental error(accuracy and precision), and statistical methods for dataanalysis (confidence interval, comparison of means, screeningbad data, linear regression and propagation of error). This isdone in a fairly traditional lecture mode with frequent in-class problem solving and homework assignments, followingthe first several chapters of the textbook (2).

In laboratory students use the UWEC Chem 213 LabManual to carry out the lab experiments. For all experimentsin the course students are not allowed to bring the lab manualinto the lab, but must transfer the pertinent information intotheir lab notebook before doing the experiment (3). Thisforces students to screen the experiment and write out thesteps they need to complete the procedure. Students are freeto refer to the lab manual outside the lab at any time. TheAOAC standard method format of the experiments makesthis process relatively easy and most procedures are about twopages in length.

Students are taught to use a spreadsheet (Lotus 1-2-3for Windows) in laboratory during the first several weeks ofthe semester (4). Each lab section spends two 2-hour sessionsduring lab time in a computer lab where each student is seatedat a computer. The first hour of each session is spent intro-ducing students to spreadsheet operations and the secondhour is spent by the students practicing the operations; theinstructor is present to help with problems. Students utilizean in-house guide to the spreadsheet, which is an appendixin the lab manual, to learn the operations and recall themlater. Students learn to enter different types of data, writeequations using relative and absolute addressing, move andcopy cells and ranges, use @ functions, make XY graphs, dolinear regression and graph the fitted line on the plot, andsave and recall files from floppy disks.

During the early part of the semester a student “boardof directors” is established (5, 6). This group of four to sixstudents meets once per week, with the instructor attendingevery other week, to discuss issues associated with the courseand provide feedback and advice to the instructor. Studentsvolunteer to join the board and are invited to raise any issuesand suggestions for changes they wish. A record is kept ofissues that are discussed. This board helps students recognizethat they have significant control and responsibility for thesuccess of the course.

2. Application of Concepts in Instructor-DefinedWrite-Ups

The students apply the statistical methods learned inlecture along with the spreadsheet to analyze the data andreport the results of the first five experiments, followingdetailed write-up instructions. They have occasion to utilizeeach of the statistical tests they have learned and are askedto draw conclusions from results for each experiment. Inseveral experiments they are asked to use a spreadsheet fordata analysis.

In the two aspirin analysis experiments (Experiments 3and 4 in Table 1) students work in groups of two. The groupsare structured to give each student a defined role in theexperiment and to encourage positive interdependence between

the students, a design that follows the work of John Walters(7 ). The following excerpt from a handout given to thestudents describes the group structure.

The report for each experiment consists of an initial reportincluding data analysis and experimental results submittedby the “technician” to the “manager” and a larger reportsubmitted by the manager to the instructor that includesfurther data analysis, conclusions, and answers to questionsabout the method. The technician is graded on her/his report(including accuracy and precision of the results) and themanager is graded on the technician’s report (including anycorrections the manager chooses to make to it) and her/his

own report. The comparison report is done as a team andboth students receive the same grade on it.

This structure for these experiments gives the studentsexperience working together toward a common goal andforces them to practice communication skills in a sciencecontext. There is individual accountability and a reward forworking together effectively, both of which are needed foreffective group work (8). Students are asked to use the spread-sheet and the manager is responsible for reviewing the workof the technician, so the group members naturally help oneanother gain skills. The defined roles and the instructor actingas a consultant encourage students to take ownership of theexperiment execution, data analysis, and report.

In each of the first five experiments students are givenspecific written instructions on what to include in the reportand frequently hints on how to do the calculations. By theend of those experiments they have carried out each of thestatistical tests learned in lecture at least once. However, theyhave not been asked to decide what to do and when.

3. Students Decide What To Do and What To ReportIn the next two experiments (Experiments 6 and 7 in

Table 1) students work alone to analyze vitamin C tabletsand mouthwash. They are given general guidelines for theirreports and the audience for whom the report is written. Theyare then asked to decide what data and statistical analyses to

Project Manager. This person is in charge of the experiment.It will be the manager’s responsibility to understand the experi-mental procedure, make decisions about what needs to be doneand when, and to communicate that information to the technician.The procedures are found in the lab manual and the manager’sjob is to interpret the procedure and coordinate the activities. Themanager must make use of the available resources to complete theanalyses and acquire the necessary data. In addition the managerproduces the written report in collaboration with the technicianand is graded on that report.Technician. This person is in the employ of the manager and willcarry out the procedures as indicated by the manager. Questionsshould be directed to the manager. The technician will contributeto the written report and will be graded on their contribution.Each student will play one role for the volumetric analysis and theother role for the spectrometric analysis. Three reports will becompleted by each pair of students. Each manager will completea written report for their particular experiment with help fromthe technician and a comparison report will be submitted byboth students. The instructor will act as a consultant during theanalyses. Any and all questions from the Manager will be acceptedbefore the analysis starts. After the analysis begins, questions(other than simple procedural questions) will be accepted onlywith payment of one apple.

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use and what conclusions to draw. The write-up instructionsfor the vitamin C analysis are shown below.

The instructor responds to students’ questions about thedetails of the data analysis, but not to questions about whatshould be done. The idea here is that students need to developthe ability and confidence to decide how to handle experimen-tal results to permit them to make appropriate conclusions.Giving them responsibility for asking what questions mustbe answered in the report is a good way to help them learnto solve the problems posed by the experiment (9). Havingthem do two consecutive write-ups in this format makes it

possible to give them feedback on what they have done on thefirst write-up so they can make adjustments on the second.

In the vitamin C experiment students were graded ontheir procedure description (explanation of back titrationand identification of the role of each of the important re-agents), raw data analysis (standardization calculations,calculation of vitamin C content), statistical analysis (av-erage, mean, and statistical comparison with label value),and the conclusions (statement of advice for the pharma-cist). Part of the grade was also based on how close theycame to the “correct” value for the vitamin C content—in this case, a range around the class average that also in-cluded the label value. Students lost points if any of thesecomponents were missing or if they were done incorrectly.Write-up instructions for measurement of the fluoride con-tent in mouthwash were similar to these.

The grading load in the course is not appreciablychanged by this shift in the write-up emphasis. For a groupof 56 students it takes between 3 and 5 hours to grade thereports from an experiment.

4. The Special ProjectThe final step in the process is to give students responsibil-

ity for the entire experimental process. A handout given to thestudents provides a summary of the special project (see below).

Several aspects of the special project bear comment, asfollows.

Students’ choice of a project forces them to make some

decisions and do library research with a focus. Students mustdecide what they are interested in and commit to a projectrelated to that interest. In doing this they must envision them-selves as analytical scientists, which gives the exercise a dif-

Write-Up Instructions forIodometric Titration of Vitamin C

In this write-up you will report on your analysis of over-the-countervitamin C tablets. The purpose of the analysis is to determine if thevitamin C value reported on the label is correct. The audienceis an interested pharmacist who will use the results to decidewhether to sell this product.The two-page, single-sided report should be structured as follows:1. Brief description of the procedure, illustrating your understand- ing of how the analytical technique works.2. Raw data and data analysis including sample calculations.3. Results and statistical analysis of results.4. Conclusions based on the results.You decide what results and data analysis are necessary to re-port as well as what statistical analysis is needed. You will beevaluated both on what you report as well as how well you dothe data analysis and write up the results.

NOTE: The two-page limit is a strict one; any extra pages willbe ignored.

Special ProjectFor the last several weeks of this semester you will work on ananalytical experiment of your own choice. You can work aloneor in a group of two and the scope of the project will vary withgroup size. The steps in this project are as follows:1. Choose a chemical analysis to do including a sample andanalyte and an experimental procedure.2. Write and submit a proposal that will be reviewed and ap-proved by the instructor.3. Collect the sample(s), carry out the analysis and the appro-priate calculations and statistical tests on the data.4. Present your project in a poster session during lab the lastweek of the semester.A summary of each of the steps follows.

1. Choice of ProjectChoose a chemical analysis that is of interest to you. Your interestmay be due to any aspect of your life including your job, whereyou live, what your career aspirations are, etc. Consult with theinstructor if you need some help in making this decision.The project will consist of a chemical analysis and should follow aprocedure from a standard methods book or other reference.Methods can be found in McIntyre Library by searching the key-words, “standard methods”, “official methods” and “analyticalmethods” on the NOTIS system. Please bring any checked-outmethods books to lab so others can utilize them, too.The scope of the project will vary with group size as follows:One person—Chemical analysis of sample.Two persons—Chemical analysis and investigation of some as-pect of the procedure. This might be investigation of how vary-ing an experimental parameter (e.g. temperature or pH) impactsthe result. Again, consult your instructor if you need suggestionsfor this study.

2. The ProposalA one-page proposal will be submitted to the your instructor forreview and approval. The proposal should include the following:1. Statement of the objective of the proposal, i.e. what questionwill be answered?2. Brief outline of the steps in the analysis.3. A list of all reagents and equipment needed to carry outthe analysis.The proposal is due to the instructor no later than 10 AM on Fri-day, November 15.

3. The ProjectCarry out the project in lab. Be aware that there may be sched-uling problems associated with use of single instruments like theatomic absorption spectrometer. Plan ahead.Projects must be finished by the end of the day, Thursday, Decem-ber 5.

4. The Poster Presentation

The last days of lab (Wednesday and Thursday, December 11 and12) will be spent presenting the projects and their results in a posterformat. You will prepare a poster (at least 2’ by 3’) with text inlarge print that includes: a) Title, objective and name(s). b) Descrip-tion of method. c) Data and results. d) Figures and graphs. e) Con-clusions and discussion of results. f) References.On the day of the poster presentations, you will stand by yourposter and answer questions posed by people viewing the post-ers. Students will take turns presenting their posters and visitingthe posters of fellow students.Your project and poster will be evaluated by the instructor fol-lowing a format sheet. You will be provided information on thegrading process soon.

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ferent aspect from the previous defined experiments. Alsonote that if students choose to work with a partner, the scopeof their experiment must expand to include an investigationof some aspect of the analytical procedure. This forces themto consider the factors that might influence the results of theexperiment and design an experiment to test one of thosefactors (10).

Submission of the proposal demands that students decideon their project and plan their experiment ahead of time.In addition they must identify chemical reagents and equip-ment needed to do the analysis and produce a summary ofthe procedure. This permits the instructor to provide feed-back on the scope of the projects and to advise students aboutthe probability of success, which reduces the number ofprojects that are too simple or too complex before they start.Some projects are rejected during the proposal process—usually before the formal proposal is written. Rejection isalways accompanied by plenty of suggestions for alternativeprojects that are more viable.

The laboratory is a busy place while the projects arebeing carried out. In a typical recent semester, 45 studentscompleted 38 projects (7 pairs of students were formed) and30 different analytical procedures were carried out. The largestchallenges that students face involve understanding theirprocedures and adapting them to the specific samples thatthey are analyzing. Students learn by experience that the moreyou know about the composition of the sample, the easier itis to proceed with the analysis. They also face sampling andsample handling issues that have a great impact on the results.Indeed, the entire analytical process comes into play andstudents must work hard to bring the project to a successfulconclusion. The instructor is kept busy as a consultant, helpingstudents comprehend their task without interfering in theprocess of struggle that these projects demand of students.

Several modes of reporting (oral reports, written re-ports, poster sessions) have been utilized during the years aspecial project has been done, and the poster session seemsto provide the most rewarding experience for the students.Students are provided with detailed instructions about thesize and format of the poster and the sections to be includedin it. They are also given a description of how the event will beconducted and a set of criteria that will be used to evaluate theirproject and the poster. Each lab section has a two-hour sessionwith half the students presenting their poster in each hour.

During the presentation time the nonpresenting studentsare assigned to visit at least three other posters to ask questionsand record both questions and the answers for submission.The instructor visits each poster with a checklist for evaluation.Other chemistry faculty are invited to attend (six facultyattended in a recent semester) to give students a chance to showtheir work to some more sophisticated attendees. The postersare retained by the instructor for a few days for furtherreview to complete the grading of the project and the poster.

The poster sessions are very positive and interesting sessionsand the diversity of projects is impressive. When there aresimilar projects, the results and conclusions can be compared.The students take pride in displaying their work and mostcreate fairly attractive posters and dress up for the presentation.The visits by outside faculty make the event more stimulating.All in all this is an excellent way for students to present theirprojects in a professional manner that is not too pressure-packed and to participate in a positive event at the end of

their laboratory work.

Observations and Student Evaluations

The process of helping students develop analytical skillsis constantly evolving and the steps in this process havechanged and will continue to change frequently. The processdescribed provides an appropriate mix of support for the stu-dents and development of their independence. Decisions bythe instructors about what to change and what to keep thesame have been made by observing the results of the experi-ments and projects and by surveying student opinions abouttheir experiences. Observations about the process and studentdevelopment follow.

Students learn to carry out appropriate data analysis andreporting in quantitative analysis. The student-defined labreports and the special project posters demonstrate that. Mostof the special projects in a recent semester showed that verycompetent decisions were made regarding what sort of dataanalysis to do, and the statistical analyses and conclusionswere appropriate.

The students learn to take responsibility and they gainconfidence in their abilities as a result of the laboratory ex-perience. Almost none of the students had previously donean analysis that meant anything to them and less than halfhad even heard of a poster session before the semester started.Yet the poster sessions were filled with interesting and well-done analytical projects and were well presented. Commentsby faculty members who visited the poster session have beenvery positive with regard to the overall quality of the workand the perceived value of the event to students.

Students learn to appreciate the level of commitmentnecessary to get analytical results that allow decisive state-ments to be made. During discussions at the poster sessionsmany of the students were aware of what they could and couldnot say about their results. There were also a significantnumber who needed to do more with their data or had somecalculation errors that invalidated the reported results. Duringdiscussions these students recognized that they needed to domore work after the experiment to dig out the informationthat the analysis had to offer. Much progress has been madebut there is more to be done.

Two student surveys were done in a recent semester thatshed some light on the students’ perceptions of their experiences.The first was done after the vitamin C (Exp. 6) write-up hadbeen submitted and before the ISE (Exp. 7) write-up wassubmitted. It consisted of 10 Likert-scaled questions on lectureand 10 on lab (see Table 2). The second survey was a moregeneral course evaluation that was administered on the last dayof the semester. In both surveys students were given the op-portunity to write comments on the back of the survey form.

Based on the midsemester survey, students think the labmanual is usable (items 1 and 6) and most think the lab write-ups help them understand quantitative analysis (item 2).However, fewer understand how the write-ups have been graded(item 7) and about a quarter don’t understand the write-upinstructions (item 4). There are different ways to interpretthese last two survey results. It could be that students are notgiven the information necessary to comprehend the grading.However, as each graded write-up is returned the studentsare given time to look it over, then each part of the gradingscheme is explained and students are invited to ask questions

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either then or later. I believe that the students can understandthe grading if they choose to. One possible improvement tothe feedback would be to attach an itemized grading sheetto each graded write-up describing the criteria and pointsscored.

The students who indicated that they did not under-stand the write-up instructions were probably strugglingwith the built-in ambiguity in those instructions. It is to beexpected that some students are uncomfortable doing thewrite-ups because they haven’t been told specifically what todo and how to do it. Their discomfort is a necessary part ofthe development process and is to be expected. In writtencomments five students mentioned that the write-ups interferewith their learning, primarily owing to the fact that they don’tknow “what the instructor wants”. Again the ambiguity ofbeing forced to choose what to do and how to do it makessome students uncomfortable. The graded write-up for thefirst student-designed write-up, Experiment 6, is returned tothe students before the second, Experiment 7, is due, whichprovides feedback on the objectives and expectations. Theinstructor is not insensitive to the student concerns, but seesthe overall situation as one that aids in the development of ana-lytical and reporting skills.

In addition, many students think the reports are too long(item 8). The interpretation here is that students are comingto a realization of how much work is needed to analyze anddraw conclusions from a set of data. Compared with theirprevious lab experiences the reports are quite long, particularlyfor those students who have not had organic chemistry. How-ever, the length of the report is dictated by the tasks that arenecessary to do a complete data reduction and statisticalanalysis so that appropriate conclusions can be drawn. Recentlymore effort has been made to educate students regarding thelevel of pre- and post-experiment work that is required toanalyze and communicate results. These efforts have taken theform of comments in lecture and lab as well as devoting timeto discussing student’s write-ups when they are handed back.

Many students indicate that the laboratory grades don’treflect their learning (item 3). The percentage was the same

in the lecture portion of the course, so the students must feelthat they are working hard and not getting sufficiently highgrades. However, most students said that their experience inlab was positive (iterm 10) and most said that the course isorganized to help them learn the material. The interpreta-tion is that that students are being challenged but understandthat there is support and that the experiences are designedto help them learn.

The end-of-semester evaluation has only one item thatbears on this discussion. Thirty-seven of 38 students surveyedresponded that the instructor stimulates independent think-ing. This is interpreted to mean that they feel challenged totake responsibility for their learning and decision making inthis course.

Conclusions

Development of analytical and reporting skills can beencouraged in Quantitative Analysis by providing studentsinstruction in the basics of analysis and data handling andthen requiring the students to take responsibility for apply-ing those basics to data they collect in laboratory. A varietyof mechanisms can be used to help students recognize thatthey have the freedom and responsibility to choose to learnhow to analyze and report experimental results.

Although the teaching modes described in this articlehave required strong development efforts, they have not createda significant increase in workload. The time period duringthe special projects is intense, with a great deal of individualconsultation. However the gradual increase in student respon-sibility during the semester results in the development of skillsrequired to successfully work independently. Any extra effortrequired is gratifyingly paid off in the high quality of workand presentation seen in the special projects at the end ofthe semester.

Acknowledgments

Support for development of the cooperative group struc-ture was provided by the National Science Foundation (DUE91-50358). I thank Donald Campbell for help in the devel-opment of the course and this article.

Literature Cited

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Center, UW-Platteville: Platteville, WI, 1992.7. Walters, J. P. Anal. Chem. 1991, 63, 977A, 1077A, 1179A.8. Slavin, R. E. Psychol. Bull. 1983, 94, 429.9. Zoller, U. J. Chem. Educ. 1987, 64, 510.

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