CHEM 210 Final Exam Questions and Answers

CHEM 210 Final Exam Questions and Answers if the p-value is greater than 0.1, we generally conclude the data are consistent with the null hypothesis - Answer-true what is the best way to characterize the random error present in a measurement? - Answer-take replicate measurements of your analytes and using the standard deviation and a t-table specify an error bar with a confidence limit statistical interference assesses whether an observed phenomenon in the data can reasonably be attributed to chance or not - Answer-true suppose we collected a sample size n = 100 from some population and used the data to calculate a 95% confidence interval for the population mean. now suppose we are going to increase the sample size to n = 300. keeping all else constant, which of the following would we expect to occur as a result of increasing the sample size? - Answer-(1) the standard error would decrease, (2) the margin of error would decrease in designing a clinical trial where each subject receives both a placebo and a proposed treatment, what statistical test would be most appropriate? - Answer-paired t-test an atomic absorption analysis is to be done on the calcium in a sample of powdered milk. a 12.55 gram sample of the powder is wet ashed in nitric acid and diluted to 50.00 mL with distilled water. a 1.00 mL aliquot of this is transferred to a 50.00 mL solution using EDTA. using a wavelength of 422.6 nm in an atomic absorption experiment, this diluted sample showed an absorbance of 0.375. a standard calcium sample (treated the same way) with a known concentration of 20.0 ppm provided an absorbance of 0.859. what is the ppm of calcium in the powdered milk? - Answer-437 ppm in a 3 step serial dilution: the first dilution is 1/10, the second dilution is 1/5, and the third dilution is 1/4. what is the total dilution factor of this 3 step serial dilution procedure? - Answer-200