27 real Six Sigma & SPC questions from the Production & Plant bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is DMAIC?
Junior
A.variable control chart tracking subgroup means and ranges, with control limits at ±A2·R-bar around the grand mean
B.define, measure, analyse, improve and control, the roadmap for improving an existing process
C.performance indices that use the overall long-term standard deviation instead of the within-subgroup sigma estimated from R-bar/d2
D.(USL − LSL) divided by 6σ, the potential capability of a process ignoring how well it is centred
A.DMAIC — 3.4 defects per million opportunities, which assumes a long-term 1.5-sigma shift of the process mean
B.DMAIC — define, measure, analyse, improve and control, the roadmap for improving an existing process
C.DMAIC — out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre
D.DMAIC — measurement system study splitting variation into repeatability (equipment) and reproducibility (appraisers), acceptable below 10% of tolerance and rejected above 30%
A.Six sigma quality level — 3.4 defects per million opportunities, which assumes a long-term 1.5-sigma shift of the process mean
B.Six sigma quality level — planned variation of several factors at once, using factorial or Taguchi orthogonal arrays, to quantify main effects and interactions
C.Six sigma quality level — out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre
D.Six sigma quality level — (USL − LSL) divided by 6σ, the potential capability of a process ignoring how well it is centred
11. Which term means: "smaller of (USL − mean)/3σ and (mean − LSL)/3σ, accounting for centring, with 1.33 the usual minimum and 1.67 asked for new processes"?
A.Cpk — smaller of (USL − mean)/3σ and (mean − LSL)/3σ, accounting for centring, with 1.33 the usual minimum and 1.67 asked for new processes
B.Cpk — 3.4 defects per million opportunities, which assumes a long-term 1.5-sigma shift of the process mean
C.Cpk — define, measure, analyse, improve and control, the roadmap for improving an existing process
D.Cpk — measurement system study splitting variation into repeatability (equipment) and reproducibility (appraisers), acceptable below 10% of tolerance and rejected above 30%
14. Which term means: "performance indices that use the overall long-term standard deviation instead of the within-subgroup sigma estimated from R-bar/d2"?
A.Pp and Ppk — define, measure, analyse, improve and control, the roadmap for improving an existing process
B.Pp and Ppk — (USL − LSL) divided by 6σ, the potential capability of a process ignoring how well it is centred
C.Pp and Ppk — out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre
D.Pp and Ppk — performance indices that use the overall long-term standard deviation instead of the within-subgroup sigma estimated from R-bar/d2
A.out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre
B.measurement system study splitting variation into repeatability (equipment) and reproducibility (appraisers), acceptable below 10% of tolerance and rejected above 30%
C.variable control chart tracking subgroup means and ranges, with control limits at ±A2·R-bar around the grand mean
D.3.4 defects per million opportunities, which assumes a long-term 1.5-sigma shift of the process mean
A.X-bar and R chart — (USL − LSL) divided by 6σ, the potential capability of a process ignoring how well it is centred
B.X-bar and R chart — measurement system study splitting variation into repeatability (equipment) and reproducibility (appraisers), acceptable below 10% of tolerance and rejected above 30%
C.X-bar and R chart — out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre
D.X-bar and R chart — variable control chart tracking subgroup means and ranges, with control limits at ±A2·R-bar around the grand mean
A.define, measure, analyse, improve and control, the roadmap for improving an existing process
B.out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre
C.measurement system study splitting variation into repeatability (equipment) and reproducibility (appraisers), acceptable below 10% of tolerance and rejected above 30%
D.performance indices that use the overall long-term standard deviation instead of the within-subgroup sigma estimated from R-bar/d2
20. Which term means: "out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre"?
A.Western Electric rules — performance indices that use the overall long-term standard deviation instead of the within-subgroup sigma estimated from R-bar/d2
B.Western Electric rules — out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre
C.Western Electric rules — 3.4 defects per million opportunities, which assumes a long-term 1.5-sigma shift of the process mean
D.Western Electric rules — (USL − LSL) divided by 6σ, the potential capability of a process ignoring how well it is centred
A.measurement system study splitting variation into repeatability (equipment) and reproducibility (appraisers), acceptable below 10% of tolerance and rejected above 30%
B.performance indices that use the overall long-term standard deviation instead of the within-subgroup sigma estimated from R-bar/d2
C.define, measure, analyse, improve and control, the roadmap for improving an existing process
D.out-of-control tests such as one point beyond 3σ, two of three beyond 2σ, four of five beyond 1σ or eight in a row on one side of centre
23. Which term means: "measurement system study splitting variation into repeatability (equipment) and reproducibility (appraisers), acceptable below 10% of tolerance and rejected above 30%"?
A.Gauge R&R — smaller of (USL − mean)/3σ and (mean − LSL)/3σ, accounting for centring, with 1.33 the usual minimum and 1.67 asked for new processes
B.Gauge R&R — planned variation of several factors at once, using factorial or Taguchi orthogonal arrays, to quantify main effects and interactions
C.Gauge R&R — 3.4 defects per million opportunities, which assumes a long-term 1.5-sigma shift of the process mean
D.Gauge R&R — measurement system study splitting variation into repeatability (equipment) and reproducibility (appraisers), acceptable below 10% of tolerance and rejected above 30%
26. Which term means: "planned variation of several factors at once, using factorial or Taguchi orthogonal arrays, to quantify main effects and interactions"?
A.Design of experiments — 3.4 defects per million opportunities, which assumes a long-term 1.5-sigma shift of the process mean
B.Design of experiments — planned variation of several factors at once, using factorial or Taguchi orthogonal arrays, to quantify main effects and interactions
C.Design of experiments — smaller of (USL − mean)/3σ and (mean − LSL)/3σ, accounting for centring, with 1.33 the usual minimum and 1.67 asked for new processes
D.Design of experiments — define, measure, analyse, improve and control, the roadmap for improving an existing process
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