Answer:
σ = 3
Step-by-step explanation:
Given:
For 6 sigma level of quality z = 6
Upper Specific Limit = 350 + 18 = 368°
Lower Specific Limit = 350 - 18 = 332°
Now,
z = (USL - LSL)/6σ
where, σ is the standard deviation
the standard z value is 2 for 6 sigma level of quality
thus we have
2 = (368° - 332°)/(6 × σ)
or
σ = 3 (answer)