Historically, the Average Proportion of Defective Bars Has Been 0 $$z = 3$$

question 85

Multiple Choice

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using $$z = 3$$ . Suppose a sample had 0.044 defectives. What would be the best action to take in this scenario?

• A) Nothing; it appears to be random variation.
• B) Look for assignable causes.
• C) Change z to 2 and take another sample.
• D) Change z to 4 and continue sampling.

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Definitions:

Robustness

The ability of a statistical method or test to remain effective under a variety of conditions or assumptions, or when faced with violations of those assumptions.

Sign Test

A non-parametric test used to evaluate the difference between paired samples, based on the direction of the differences between the pairs, not their magnitude.

T Test

A statistical test used to compare the means of two groups or the mean of one group with a known value, under the assumption of normally distributed data.

T Procedure

A statistical method used to test the mean of a population, especially useful when dealing with small sample sizes and unknown population standard deviations.