MATH 302_Week 5Test_Q3_Q4 Attempt1

Consider the following sets of replicate measurements: (1) Calculate the mean and standard deviation of Group A. (2) Determine the confidence interval at 95% confidence level. Assume the data here are the only knowledge you have and no previous measurements are available.

Student A got the following densities of water; 1.09g/mL, 1.14g/mL, and 1.15g/mL with an average of 1.127 g/mL and a standard deviation of 0.026 g/mL. Student B determined the density of water to be 1.04 ± 0.05 g/mL. Determine the acceptable range of mass when you are asked to obtain 3.000g of NaCl.

A student determines the concentration of an unknown sample using two different methods. Each method has three different trials; the average, standard deviation, and percent error produced by each method is listed below. Method 1 Average: 10.56 M NaOH Standard deviation: 1.35 M NaOH Percent error: 1.25% Method 2 Average: 10.92 M NaOH Standard deviation: 1.02 M NaOH Percent error: 3.45% Which method was more accurate? How can you tell?

Determine the Average Mass and the Standard Deviation for the following data: Mass of pennies in grams = 1.5021, 1.4736, 1.4966, 1.5164, 1.5420, 1.4699 g. Average Mass grams +/- Standard Deviation grams

You measure 35 turtles' weights, and find they have a mean weight of 72 ounces. Assume the population standard deviation is 3.1 ounces. Based on this, construct a 99% confidence interval for the true population mean turtle weight. Give your answers as decimals, to two places ounces

A student determines the concentration of an unknown sample using two different methods. Each method has three different trials; the average, standard deviation and percent error produced by each method is listed below. Method 1 Average: 10.56 M NaOH Standard deviation: 1.35 M NaOH Percent error: 1.25% Method 2 Average: 10.92 M NaOH Standard deviation: 1.02 M NaOH Percent error: 3.45% Which method was more precise? How can you tell?

The gold content of an ore is being measured. The results of these analyses are:  Content (ppt) 20.065 19.999 21.054 20.533 20.088 20.112 What is the average value, standard deviation and confidence interval for this set of data?Show each step of the calculation. Using your results calculate the %accuracy and %precision (relative standard deviation) if the true value is 20.045%.

A chemical analysis yields masses of Zn that are higher by 2 mg compared to the expected value. Calculate the percentage relative error if the true mass of Zn in the sample is 125 mg. O 100.4% O 0.8% 98.4% O 1.6%

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A chemical industry discharges a waste contaminated with trichloroethylene (TCE) to the city sewer system. By law, the concentration of TCE must be 1 mg/L or less. To enforce this law, the Department of Environmental Conservation (DEC) conducts random testing. The chief environmental engineer for the chemical company knows that the mean TCE concentration in the waste is 0.064 mg/L, and the standard deviation is 0.022 mg/L. The TCE concentration can be assumed to be a normal random variable. What is the probability that the company will fail a random test by the DEC? [In other words, the probability that a random sample will have TCE > 0.1 mg/L.] Show your work and draw a labeled sketch to show what area of the normal distribution curve you used to solve the problem. What is the probability that the company will fail two consecutive random tests? The tests can be assumed to be independent of each other. Show your work. Determine the concentration of TCE that is exceeded only 10%…

1. A graduated cylinder with a least count of ± 0.5 ml is used in a density experiment. The initial water level, before inserting the irregular shaped solid, is 30.0 ml. After inserting the solid, the water level is 34.5 ml. What is the probable error in the volume of the solid? What is the probable percent error in the volume of the solid?

Analytical Chemistry

Please type answer note write by hend.

Estimate the absolute standard deviation (or uncertainty) for the results of the following calculations. Round each result so that it contains only  significant digits. The numbers in parentheses are absolute standard deviations. Show  your solution and express the final answer and its  corresponding uncertainty. a)  y= 2.998(±0.002)   - 3.98 (±0.15) + 9.035 (±0.002) = 8.0531 b)  y= 39.2(±0.3) x 3.054 (±0.022) x 10^ -2 = 1.197   c)   y= [198(±6)   - 89 (±3)] / 1335 (±2) + 64 (±7)]  = 7.791 x 10^-2

Using a 25mL pipette, you prepare a standard solution by pipetting 25.00mL of the standard iron solution[0.25g/L] into a 500mL volumetric flask. Then, using a 10mL pipette you transfer a 4mL aliquot of this solution into a 50mL volumetric flask and dilute up to the mark. Calculate the % uncertainty.   Question 1 options:   0.65   0.75   0.0075   0.45

A quantitative analysis for an analyte gives a mean concentration of 12.6 ppm. The standard deviation due to the method, sm, is found to be 1.1 ppm, and that due to sampling, ss, is 2.1 ppm. By how much does the overall variance change if sm is improved by 10% and ss is improved by 15%?

Suppose a student completes an experiment with an average value of 2.9 mL and a calculated standard deviation of 0.66 mL. What is the maximum value within a 1 SD range of the average?

Please answer.

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:

A powder was prepared containing 3.00% NaCN and 97.00% NaCl. A sample obtained from that mixture containing 7.374×10^5 particles weighs 10.0 g. Determine the number and percent relative standard deviation of NaCN particles from a sample of the mixture weighing 6.30 g. I need nNaCN particles and %RSD

Estimate the absolute deviation(or uncertainty) for the results of the following calculations. Round each result so that it contains only significant digits. The numbers in parentheses are absolute standard deviations. Finally, write the answer and its uncertainty.a.) Y= 6.75 (± 0.03) + 0.843(±0.001) - 5.021 (±0.001) = 2.572b.) Y= 19.97(± 0.04) + 0.0030(±0.0001) + 4.29(±0.08) = 24.263c.) Y= 143(± 6) - 64(±3) = 5.9578 x10-21249 (±1) +77 (±8)

2. A study of body mass index (BMI) in adults showed that for men aged 40–44, the mean BMI level is 26.7 with a standard deviation of 3.7. Assuming a normal distribution, what percentage of men in this age group have a BMI between 30.0 and 35.0?

Average and Uncertainty The molar mass of an unknown compound was determined in three repeat experiments. The molar masses obtained were 82.23, 81.55 and 82.00 g/mol. Assume the uncertainty in the average value to be the half range. Enter the average value and its uncertainty, both rounded to the appropriate number of digits (according to the Rules outlined in the Chem121 Lab Manual Appendix). g/mol

3) For the results, discuss the significance of the following in terms of accuracy or precision: a) Deviation vs Absolute Error. b) % Error vs Standard Deviation.