As the Quality Control Manager of a chemical company, you are asked to decide between several process methods that are supposed to uniformly mix 37.4 milligrams into a chemical solution. The resulting solutions from each process are sample tested for uniformity. The test samples yielded the following results of percentage powder mixed in the solution:

Which method would be the best choice to provide a uniform mixture??? (Hint: The best selection would be that resulting in the lowest standard deviation of measurements
Method A
Method B
Method C
Method D

Solution Preview

Standard Deviation:
The standard deviation is the square root of the average squared deviation from the mean.

Method A: Consider the observations: 0.13%, 0.21%, 0.009%, 0.014%
1. First, calculate the mean and determine N.
2. Remember, the mean is the sum of scores divided by N where N is the number of samples.
3. Therefore, the mean = (.13 + .21 + .009+ .014) / 4 or .09075
4. Then, calculate the standard deviation as illustrated below.
squared
sample mean ...

Solution Summary

The lowest standard deviation of measurements is calculated. The excel calculations are copied into a word document which is also in the solution text box.

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Table 1 Net Sales (in thousands)
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Median = $6,348,797
StandardDeviation = $2,473,

An elf at the Keebler factory checks to see that packages of cookies are properly filled by randomly selecting six packages from a box of 50 and weighing them. He makes the following measurements in ounces:
{17, 18, 18, 16, 16, 15}.
What is the standarddeviation?

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Interval Observed Frequencies
39.99 or less 12
40 - 59.99 18
60 - 79.99 15
80 and higher 5
50
It is desired to test whether these measurements

See the attached file.
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