A control chart for defects per unit uses 3-sigma limits. The central line on the control chart is at 2.0. The limits vary with the value of n. Determine the correct position of these upper and lower control limits when n = 6:
(A) 3.26, 0.73 (B) 3.73, 0.27 (C) 2.63, 1.37 (D) 2.29, 0.00 (E) None of the above
10. What is a major advantage of 'np-chart? (A) Can be used for variable sample sizes (B) More accurate than P-charts (C) Simplicity of understanding and use (D) Requires smaller sample size