Question
OCR J560/03 — Foundation (calculator)
A factory tests 800 light bulbs. 24 are faulty.
(a) Estimate the probability that a randomly selected bulb is faulty. [1] (b) The factory produces 50 000 bulbs per day. Estimate how many are faulty. [2] (c) The factory wants to improve testing — they retest a sample of 50 bulbs and find 1 faulty. State whether this changes your earlier estimate, and why. [2]
5 marks · take your time before peeking.
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