Time allowed: Three hours. Total marks: 60 marks.
There are FIVE questions in this examination; each starts on a fresh page. Answer ALL five questions; start each answer on a fresh page. All questions carry equal marks. The value of each sub-question is indicated in brackets. On the front of your answer book, write the number of each question you have attempted. Statistical tables and useful formulae are attached to this examination paper. Electronic calculators may be used. The examination paper may be retained by the candidate. Answers must be written in black or blue ink. Pencils may be used only for drawing, sketching or graphical work. Show the working steps in your answers.
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Question 1 (a) Consider the following binomial distribution :
Answer the following based on the above distribution: (i) What can you say about the skewness of this …show more content…
Explain what it means to say that is efficient relative to .[1 mark] Production of a gadget takes two tasks that have to be completed in succession. The time it takes to complete task one is distributed normally with mean 35min and standard deviation 6min. The time it takes to complete task two (that starts right after task one is completed) is independent of time it takes for task one and is also distributed normally with mean 22min and standard deviation 3min. What is the probability that the production of a gadget takes no more than one hour? [2 marks]
(iii) After production is completed, every gadget goes into quality assurance. Experience shows that the quality of about 10% of gadgets is rejected. If 360 gadgets enter quality assurance a day, what is the probability that at least 320 gadgets pass the quality test in one day? [1 mark]
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