The Importance and Efficacy of Using Statistics in the High School Chemistry Laboratory

Matsumoto, Paul S.

doi:10.1021/ed083p1649

Cited by 7 publications

(11 citation statements)

References 7 publications

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“…The t -test compares the means of two independent groups to determine whether there is statistical evidence that the associated population means are significantly different, within the confidence level of 95%. ,,,,, …”

Section: Resultsmentioning

confidence: 99%

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Quantitative Analysis Using a Flatbed Scanner: Aspirin Quantification in Pharmaceutical Tablets

Silva

Borges

2019

J. Chem. Educ.

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Here, students determine aspirin (acetylsalicylic acid) mass in pharmaceutical tablets using a colorimetric method. Aspirin, salicylate, and salicylic acid do not absorb visible light. Thus, in alkaline medium, acetylsalicylic acid was hydrolyzed to salicylate; then, it was reacted with an acidic Fe(III) solution, and a violet complex was formed. Quantitative analysis was carried out using absorbance measured at 535 nm (standard method) and digital images obtained with a flatbed scanner (proposed method). Results obtained with both methods were compared using an F-test and a t-test; both methods had shown equivalent accuracy and precision at the 95% confidence level. In addition, one-way ANOVA showed that aspirin masses found by five student groups using both methods are equivalent at the 95% confidence level. In the proposed method, samples were placed in a 96 microwell plate, and RGB values were extracted automatically from all wells in less than 5 min using ImageJ's plugin "ReadPlate"; data obtained were organized using a spreadsheet to determine aspirin mass in pharmaceutical tablets, recovery, and percent error. Our goal was to design a portable, cost-effective, and user-friendly platform and to develop an experimental methodology that can easily be applied to any research and education laboratory using just a flatbed scanner.

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Section: Resultsmentioning

confidence: 99%

“…Statistics is a powerful tool with applications in chemistry, the health sciences, and the social sciences. 44 Comparing the proposed method with the standard method may be used to teach statistical analysis.…”

Section: Statistical Test Resultsmentioning

confidence: 99%

Quantitative Analysis Using a Flatbed Scanner: Aspirin Quantification in Pharmaceutical Tablets

Silva

Borges

2019

J. Chem. Educ.

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“…The t -test compares the means of total phenolic contented obtained with the proposed method and the standard method to determine whether there is statistical evidence that the associated means are significantly different (accuracy). ,,− …”

Section: Resultsmentioning

confidence: 99%

“…Significance tests were carried out using the Excel Analysis ToolPack. For a complete description of the significance tests see the Student laboratory handout in the Supporting Information. ,,− …”

Section: Materials and Methodsmentioning

confidence: 99%

“…The main student learning goal was comparing the proposed method with the standard method using two-tailed significance tests, and then comparing the total phenolic content between beers using one-tailed significance tests. ,,− In addition, students are introduced to one of the most widespread colorimetric methods in food science (Folin–Ciocalteu assay). As a result of performing these experiments, it is expected that students Understand the basic principles of molecular spectroscopy Identify the chemical principles used on the protocols for Folin–Ciocalteu assay Do quantitative analyses using digital images obtained with a flatbed scanner Understand and use significance tests Understand the difference between one-tailed and two-tailed significance tests …”

Section: Students’ Learning Goalsmentioning

confidence: 99%

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Using a Flatbed Scanner and Automated Digital Image Analysis To Determine the Total Phenolic Content in Beer

2019

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Here, students determine the total phenolic content in beers using the Folin–Ciocalteu assay. The Folin–Ciocalteu reagent is a yellow complex, in an alkaline medium; it reacts with phenols and non-phenolic reducing substances to form a blue complex. Quantitative analysis was carried out using absorbance measured at 765 nm (standard method) and digital images (proposed method). In the proposed method, samples were placed in a 96 microwell plate; then, a plate image was obtained with a flatbed scanner. The ImageJ plugin ReadPlate extracts red (R)-values from all wells of the scanned image at the same time; then, R-values were exported to a spreadsheet that converted these values to absorbances. Using absorbances obtained with R-values, the spreadsheet also provides standard calibration plots, limits of detection (LODs), limits of quantification (LOQs), and beer sample total phenolic contents. The proposed method and the standard method were compared using two-tailed significance tests; students observed that both methods provide equivalent results, that both methods were linear in a 2–10 mg L–1 gallic acid concentration range, and that both methods had close LODs and LOQs, 0.55 and 1.70 gallic acid mg L–1, respectively. Beer sample total phenolic contents were compared using one-tailed significance tests. This laboratory experiment provides an effective instrumental alternative to spectrophotometric methods, which can be especially beneficial, where purchasing and maintaining a spectrophotometer is a challenge, and it also presents to the students one-tailed and two-tailed significant tests.

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Hypothesis Tests and Exploratory Analysis Using R Commander and Factoshiny

Borges

2022

J. Chem. Educ.

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An understanding of statistical concepts is necessary for a chemist with a complete education. Here, statistical tests were taught using the R Commander and the Factoshiny packages. These packages run on R software and have a graphical user interface (GUI), which allows students to do statistical tests quickly and easily. These packages were presented through 14 case studies. In each case study, a data set was provided in MS Excel format, and a series of questions were answered using these packages. Hypothesis tests and exploratory analysis (principal component analysis; PCA) were taught using R Commander and Factoshiny, respectively. Outlier results were found using boxplots. Data normality was checked using histograms and the Shapiro− Wilk test. Normally distributed data sets were compared using parametric hypothesis tests (t test, paired t test, one-way ANOVA, two-way ANOVA, one-way repeated measure ANOVA). Non-normally distrusted data sets were compared using nonparametric tests (Wilcoxon, Kruskal−Wallis, and Friedman tests). Results provided by these parametric and nonparametric tests were also verified using plots (plot of means and boxplots).

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The Importance and Efficacy of Using Statistics in the High School Chemistry Laboratory

Cited by 7 publications

References 7 publications

Quantitative Analysis Using a Flatbed Scanner: Aspirin Quantification in Pharmaceutical Tablets

Quantitative Analysis Using a Flatbed Scanner: Aspirin Quantification in Pharmaceutical Tablets

Using a Flatbed Scanner and Automated Digital Image Analysis To Determine the Total Phenolic Content in Beer

Hypothesis Tests and Exploratory Analysis Using R Commander and Factoshiny

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