GATE 2022 PI – Question 57

Quality and Reliability · Quality Management · 2 marks · Numerical answer

Five samples of 80 mobile screens have defective counts 4,10,5,6,5. Find the p-chart upper control limit using ±3σ, as fraction defective to two decimals.

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Correct answer: 0.15 to 0.18

Explanation

Mean fraction is $\bar p=30/(5\times80)=0.075$. Standard error is $\sqrt{\bar p(1-\bar p)/80}=0.02945$. Upper limit = 0.075+3(0.02945) = 0.16334, rounding to **0.16**.

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