Statistics homework help.
 Define Common cause variation.
 Define assignable cause variation.
 In the day to day operations of the process why is it important that we understand if the variation we see in a product/process comes from common or assignable cause situations?
 Define a population.
 Define a sample:
 Define a random sample:
 Define a stratified sample and give one example.
 For the following set of sample data calculate each of the values below:
Sample data set: 11, 10, 8, 13, 14, 12, 11, 11, 13, 11, 11
Mean:
Median:
Mode:
Range:
 What are the two key principles you try to follow when conducting a brainstorming session? (4 points)
 Create a Pareto Diagram from the following data.
Type of Defect  Number of Defects 
Overesize Diameter  20 
Undersize Diameter  6 
Rusty  14 
Scratched  5 
Excessive Tool Marks  11 











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 What advantage does a Cause & Effect Diagram offer over traditional brainstorming sessions?
 Determine the area under the normal curve for each of the following conditions. Diagram required.
 Area under the curve > Z = 1.34
 Area under the curve between Z = 2.15 and Z = 0.45
 Area under the curve < Z = 1.89
 Area under the curve < Z = 1.65 and > Z = 2.10 (Note: both areas)
13) The output for a normally distributed process results in an average size of 43 Rc with a standard deviation of 2.1 Rc”. If the customer specifications are 40 Rc to 52 Rc, are there defective products being made? Mathematical analysis required for credit.
 What is a requirement of the data collections process to be able to use a “run” chart? (4 points)
 If the customer specifications are in pounds and are 13.00 ± 0.15, given the following histogram, are defective parts being made? Justify your answer to receive credit. (4 points)