(a)
Interpretation:
The standard deviation and relative standard deviation for count 100 are to be determined.
Concept introduction:
The standard deviation can be calculated as follows:
Also, the relative standard deviation can be calculated as follows:
(b)
Interpretation:
The standard deviation and relative standard deviation for count 850 are to be determined.
Concept introduction:
The standard deviation can be calculated as follows:
Also, the relative standard deviation can be calculated as follows:
(c)
Interpretation:
The standard deviation and relative standard deviation for count 8.00×103 are to be determined.
Concept introduction:
The standard deviation can be calculated as follows:
Also, the relative standard deviation can be calculated as follows:
(d)
Interpretation:
The standard deviation and relative standard deviation for count 4.00×104 are to be determined.
Concept introduction:
The standard deviation can be calculated as follows:
Also, the relative standard deviation can be calculated as follows:
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PRINCIPLES OF INSTRUMENTAL ANALYSIS
- 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)?arrow_forwardA method for the determination of the corticosteroid methylprednisolone acetate in solutions obtained from pharmaceutical preparations yielded a mean value of 3.7 mg mL with a standard deviation of 0.3 mg mL. For quality control purposes, the relative uncertainty in the concentration should be no more than 3%. How many samples of each batch should be analyzed to ensure that the relative standard deviation does not exceed 9% at the 95% confidence level? samplesarrow_forwardTrial Mass (g) 1 48.8839 2 49.0099 3 49.1121 4 48.9342 5 49.0338 6 48.7798 Calculate mean and standard deviation in the correct number of sigfigsarrow_forward
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- 8) Two different analytical methods are compared for determining Ca. The following are two sets of data. Set 1 Set 2 155.779 155.784 155.787 155.787 155.813 155.765 155.781 155.793 i. i. Determine the mean and the standard deviation in Set 1. Calculate the 95% confidence limit for data in Set 1. Identify a possible outlier in Set 2. Use the Q-test to determine whether it can be retained or rejected at 95% confidence level. ii.arrow_forwardEstimate the absolute deviation and the coefficient of variation for the results of the calculation below. Round off the result so that it contains only the significant digits. The numbers in parentheses are absolute standard deviations.arrow_forwardThe glucose concentrations in a patient with mildly elevated glucose levels were determined by a spectrophotometric analytical method and were recorded in mg/L as follows: 799, 745, 750, 774, 777, 800, 758 and the true value is 792. (a) Calculate the standard deviation (b) Calculate the relative error in ppmarrow_forward
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