Water contents in oil was measured 4 times by each of two methods with the following results: Method 1: 31.40, 31.24, 31.18, 31.43 ppm. Method 2: 30.70, 29.49, 30.01, 30.15 ppm. Are the precisions (Standard deviations) * significantly different at the 95% confidence level? Both precision and accuracy are same O They are not significantly different. O They are significantly different. O F calculated < F table, so standard deviations are significantly different. O

Water contents in oil was measured 4 times by each of two methods with the following results: Method 1: 31.40, 31.24, 31.18, 31.43 ppm. Method 2: 30.70, 29.49, 30.01, 30.15 ppm. Are the precisions (Standard deviations) * significantly different at the 95% confidence level? Both precision and accuracy are same O They are not significantly different. O They are significantly different. O F calculated < F table, so standard deviations are significantly different. O

Appl Of Ms Excel In Analytical Chemistry

2nd Edition

ISBN:9781285686691

Author:Crouch

Publisher:Crouch

Chapter4: Least-squares And Calibration Methods

Section: Chapter Questions

Problem 4P

See similar textbooks

Similar questions

Hexane (C6H14, density = 0.766 g/cm3), perfluoro-hexane (C6F14, density = 1.669 g/cm3), and water are immiscible liquids; that is, they do not dissolve in one another. You place 10 mL of each in a graduated cylinder, along with pieces of high-density polyethylene (HDPE, density = 0.97 g/cm3), polyvinyl chloride(PVC, density = 1.36 g/cm3), and Teflon (density = 2.3 g/cm3). None of these common plastics dissolves in these liquids. Describe what you expect to see.
A group of students took turns using a laboratory balanceto weigh the water contained in a beaker. The results theyreported were 111.42 g, 111.67 g, 111.21 g, 135.64 g,111.02 g, 111.29 g, and 111.42 g.(a) Should any of the data be excluded before the average is calculated?(b) From the remaining measurements, calculate the average value of the mass of the water in the beaker.(c) Calculate the standard deviation s and, from it, the 95% confidence limit.
over a course of multiple trials a student measures the density of methanol to be 0.707 g/mL, 0.799 g/mL, and 0.780 g/mL. calculate the average density, the deviation of each measurement and standard deviation of all data points.
Which of the following represents the precision of a set of measurements? A student used water displacement method to measure the density of a metal. The average result of five attempts was 2.763 g/mL, and the calculated standard deviation was 0.026 g/mL. How should the result be reported in a "mean +/- st. dev." format? The molar mass of butane (C4H10) is 58 g/mol. If a student measured the molar mass of butane to be 63, what is the % error of the measurement? Use no decimal place when entering the answer. Several balloons of He gas are kept at the same temperature, but different pressure. At which pressure does the gas have the lowest density?
4. A student measures the density of an Unknown liquid 3times and obtains an average density of 0.705g/mL with a Standard Deviation of 0.352g/mL. 1.What can you say.If anything about the Precision of the measurements? 2.What can you say if anything about the Accuracy of the average density?
Which instrument(s) has (have) the greatest precision for measuring volume: 10 mL graduated cylinder, 50 mL graduated cylinder, 50 mL buret, 10 mL volumetric pipet, or 10 mL graduated pipet? Explain why this (these) instrument(s) have the greatest precision. Which of those instruments would be best if you need to deliver a precise volume into a solution but you do not know ahead of time what that volume would be?
What is the difference between a qualitative and quantitative measurement?
The density of an irregular shaped object was measured three times with the following results: 2.15 g/cm3 2.79 g/cm3 1.98 g/cm3 How would you report the mean and standard deviation of this data? a. 2.31 g/cm3 ± 0.07 g/cm3 b. 2.307 g/cm3 ± 0.1 g/cm3 c. 2.4 g/cm3 ± 0.5 g/cm3 d. 2.15 g/cm3 ± 0.03 g/cm3 e. 2.3 g/cm3 ± 0.4 g/cm3