A new method was created to determine arsenic in rice. To validate this method, a reference standard was used with a certified concentration of 2.1 ppm of Arsenic, with a standard deviation of 0.7 ppm . When analyzing the reference standard 7 times, with the new method, an average of 2.87 ppm was obtained with a standard deviation of 0.4 ppm. These results show that the new method Has it been validated? Does it have systematic errors? Has a precision similar to that of the reference standard

What is limit of detection? What is standard deviation?

Find the result (c) and the absolute standard deviation (sc) as propagated in the following calculation. Express final result and its propagated standard deviation with an appropriate number of significant figures. a = 5.75 (+0.05)+0.833 (±0.001); b = 3.75 (±0.02);c = alb

The following densities of water were obtained by Student A: 1.07 g/mL, 1.14 g/mL, and 1.13 g/mL. Show how Student A determined the density of water to be 1.11 ± 0.04 g/mL. Calculation for the average = 1.11 g/mL: Calculation for the standard deviation = 0.04 g/mL:

How would you calculate Standard Deviation?

An ore sample was analyzed for its Fe content. Student A analyzed the sample a total of six times and her results had a standard deviation of 1.33. The same sample was analyzed five times by Student B and his results had a standard deviation of 3.42. To determine if their standard deviations are similar, they perform an F test. The calculated F value is and the table value of Fis 3 in your book for critical values of F. O 6.61; 7.39 O 6.61; 9.36 O 0.151; 9.36 O 2.57; 7.39 O 6.61; 6.98 Refer to Table 4-

From the following data, calculate the concentration of the analyte in the sample read at 700 nm: Absorbance of unknown sample = 0.807 Absorbance of a 130 mg/dl standard = 0.234 Do not answer in image format. Maintain accuracy and quality in your answer. Answer completely.

You are developing a procedure for determining traces of copper in biological materials using a wet digestion followed by measurements by atomic absorption spectrophotometry. In order to test the validity of the method, you obtain a NIST orchard leaves standard reference material and analyze this material with your procedure five times and obtain a mean of 12.27 ppm with a standard deviation of 0.097 ppm. The NIST sample is listed as 11.7 ppm. Does your method give a statistically valid value at the 95% confidence level?

Replicate tests showed the following lead content results of a blood sample: 0.752, 0.756, 0.752, 0.751, and 0.760 ppm Pb. Calculate the (a) the mean (b) the standard deviation (c) the variance (d) the relative standard deviation in parts per thousand, (e) the coefficient of variation, and (f) the spread.

As part of an analytical chemistry laboratory course, a student measured the Ca2+ content in two water samples, city-supplied drinking water and well-supplied drinking water, using two different analytical methods, flame atomic absorption spectrometry (FAAS) and EDTA complexometric titration. The results of this experiment are given in the table as the mean Ca2+concentration (?¯) and standard deviation (?) in parts per million (ppm). Each sample was measured five times (n=5) by each method. Method City-Supplied Drinking Water (?¯±?x¯±s) Well-Supplied Drinking Water (?¯±?x¯±s) FAAS 57.57±0.68 ppm 64.77±0.70 ppm EDTA titration 58.32±0.96 ppm 65.62±0.97 ppm Method Comparison: For each drinking water sample (city and well), compare the Ca2+ content measured by FAAS and EDTA titration. Calculate the ? value for each sample. Do the methods produce statistically different results at the 95% confidence level when measuring the Ca2+content of the city-supplied drinking water? Do the…