Which of the following is true of a p-chart? A)The lower control limit is found by subtracting a fraction from the average number of defects. B)The lower control limit indicates the minimum acceptable number of defects. C)The lower control limit equals D₃ times p-bar. D)The lower control limit may be at zero. E)The lower control limit is the same as the lot tolerance percent defective.

Question

Quizplus · Accepted Answer

The lower control limit (LCL) on a p-chart may be at zero if there are no defects in a given sample. The LCL is calculated using the formula LCL = p-bar - 3*sqrt(p-bar*(1-p-bar)/n), where p-bar is the average proportion of defects in the samples and n is the sample size. The LCL indicates the threshold at which the process is considered out of control and should be investigated. It does not indicate a minimum acceptable number of defects, nor is it equivalent to the lot tolerance percent defective. Option A is incorrect because the fraction should be added to the average number of defects, not subtracted. Option C is incorrect because it does not represent the actual formula for calculating the LCL.

Which of the Following Is True of a P-Chart