CHEM 210 Final Exam
Questions and Answers
1. if the p-value is greater than 0.1, we generally conclude the data are consis-
tent with the null hypothesis: true
2. what is the best way to characterize the random error present in a mea-
surement?: take replicate measurements of your analytes and using the standard
deviation and a t-table specify an error bar with a confidence limit
3. statistical interference assesses whether an observed phenomenon in the
data can reasonably be attributed to chance or not: true
4. 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.
1/5
, 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?: (1) the standard error would decrease, (2) the
margin of error would decrease
5. in designing a clinical trial where each subject receives both a placebo and
a proposed treatment, what statistical test would be most appropriate?: paired
t-test
6. 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?: 437 ppm
7. in a 3 step serial dilution: the first dilution is 1/10, the second dilution is 1/5,
2/5
Questions and Answers
1. if the p-value is greater than 0.1, we generally conclude the data are consis-
tent with the null hypothesis: true
2. what is the best way to characterize the random error present in a mea-
surement?: take replicate measurements of your analytes and using the standard
deviation and a t-table specify an error bar with a confidence limit
3. statistical interference assesses whether an observed phenomenon in the
data can reasonably be attributed to chance or not: true
4. 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.
1/5
, 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?: (1) the standard error would decrease, (2) the
margin of error would decrease
5. in designing a clinical trial where each subject receives both a placebo and
a proposed treatment, what statistical test would be most appropriate?: paired
t-test
6. 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?: 437 ppm
7. in a 3 step serial dilution: the first dilution is 1/10, the second dilution is 1/5,
2/5
