A set of samples from an abandoned industrial site detected a suspected groundwater contaminant at a mean concentration of 0.045 µg/L with a standard deviation of 0.007 µg/L. How many samples are required to be collected at a confidence level of 95% and power of 90% if the mean background concentration of the contaminant is 0.035 µg/L? О А.З О В. 4 С. 5 O D. 6

A set of samples from an abandoned industrial site detected a suspected groundwater contaminant at a mean concentration of 0.045 µg/L with a standard deviation of 0.007 µg/L. How many samples are required to be collected at a confidence level of 95% and power of 90% if the mean background concentration of the contaminant is 0.035 µg/L? О А.З О В. 4 С. 5 O D. 6

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter7: Statistical Data Treatment And Evaluation

Section: Chapter Questions

Problem 7.13QAP

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A set of samples from an abandoned industrial site detected a suspected groundwater contaminant at a mean concentration of 0.045 µg/L with a standard deviation of 0.007 µg/L. How many samples are required to be collected at a confidence level of 95% and power of 90% if the mean background concentration of the contaminant is 0.035 µg/L? О А.3 В. 4 О С.5 O D. 6
A volume of 250 ml of a 0.05 M solution of a reagent of formula weight (relative molecular mass) 40 was made up, the weighing being done by difference. The standard deviation of each weighing was 0.0001 g. 1 (a) What were the standard deviation and relative standard deviation of the weight of reagent used?
For the determination of iron in used jet engine oil, 30 analyzes with 3 repetitions each were made by atomic absorption method and the standard deviation was found s=2.4 µg Fe/mL. Since this standard deviation value is close to the ϭ value, the iron concentration of 18.5 µg Fe/mL(a) by a single analysis,(b) as the average of the two analyzes,(c) Calculate the 80% and 95% confidence intervals if found as the mean of four analyses.
A young researcher was evaluating a standard method for determining the methylmercury content in blue fin tuna using high performance liquid chromatography (HPLC). She determined the standard deviation (?)(s) for the method to be 0.440.44 ppb and assumed that ?s was a good approximation of ?σ . As a test, she used this method to evaluate the methylmercury content in a National Institutes of Standards and Technology (NIST) standard and determined the unknown amount to be within 0.210.21 ppb (?)(μ) of the known mean with 99% probability. How many replicate measurements of the NIST standard did the researcher perform?
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A clinical chemist obtained the following data for the alcohol content of a sample of blood: % C2H5OH: 0.084, 0.089, and 0.079. Calculate the 95% confidence interval for the mean assuming that (a) the three results obtained are the only indication of the precision of the method and that (b), from previous experience on hundreds of samples, we know that the standard deviation of the method s 5 0.005% C2H5OH and is a good estimate of s.
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Can you please fill the rest of tghe data based on the on inforamtion you have and answer Average concentratuon of NaOH Standard deviation of concentration
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A solution is prepared by weighing 5.0000 g of cesium iodide into a 100-mL volumetric flask. The balance used has a precision of 0.2 mg reported as a standard deviation, and the volumetric flask could be filled with a precision of 0.15mL also reported as a standard deviation. What is the estimated standard deviation of concentration (g/mL)?
Review Question 5b and 5c) 5B) Volume of a 20-mL pipet: 20.0145mL 20.0056mL 20.0256mL 20.0114mL 5C) Concentration of NaOH: 0.1456 M 0.1259 M 0.1489 M 0.1356 M
A titrimetric method for the determination of calcium in limestone was tested by analysis of an NIST limestone containing 30.15% CaO. The mean result of four analyses was 30.26% CaO, with a standard deviation of 0.085%. By pooling data from several analyses, it was established that s   = 0.094% CaO.a. Do the data indicate the presence of a systematic error at the 95% confidence level?b. Do the data indicate the presence of systematic error at the 95% confidence level if no pooled value for s was available?