St. Britto Hr. Sec. School - Madurai
12th Business Maths Weekly Test - 1 ( Probability Distributions)-Aug 2020
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A manufacturer of metal pistons finds that on the average, 12% of his pistons are rejected because they are either oversize or under size. What is the probability that a batch of 10 pistons will contain
(a) no more than 2 rejects? (b) at least 2 rejects?
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Write down the conditions in which the Normal distribution is a limiting case of binomial distribution.
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The birth weight of babies is Normally distributed with mean 3,500g and standard deviation 500g. What is the probability that a baby is born that weighs less than 3,100g?
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A fair coin is tossed 6 times. Find the probability that exactly 2 heads occurs.
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Find the value of K if X is a normal variate whose p.d.f is given by f(x) = \(\frac1K\)\({e }^{ { 8x-4x }^{ 2 } }\), -\(\infty\) < X < \(\infty\)
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The marks obtained in a certain exam follow normal distribution with mean 45 and SD 10. If 1,300 students appeared at the examination, calculate the number of students scoring
(i) less than 35 marks and
(ii) more than 65 marks.
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A and B play a game in which their chance of winning are in the ratio 3:2 Find A’s chance of winning atleast three games out of five games played.
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If on an average 1 ship out of 10 do not arrive safely to ports. Find the mean and the standard deviation of ships returning safely out of a total of 500 ships.
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If the chance of running a bus service according to schedule is 0.8, calculate the probability on a day schedule with 10 services :
(i) exactly one is late
(ii) atleast one is late -
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Marks in an aptitude test given to 800 students of a school was found to be normally distributed 10% of the students scored below 40 marks and 10% of the students scored above 90 marks. Find the number of students scored between 40 and 90?
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20% of the bolts produced in a factory are found to be defective. Find the probability that in a sample of 10 bolts chosen at random exactly 2 will be defective using
(i) Binomial distribution
(ii) Poisson distribution (e-2 = 0.1353)
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If the height of 300 students are normally distributed with mean 64.5 inches and standard deviation 3.3 inches find the height below which 99% of the student lie?
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One fifth percent of the the blades produced by a blade manufacturing factory turn out to be defective. The blades are supplied in packets of 10. Use Poisson distribution to calculate the approximate number of packets containing no defective, one defective and two defective blades respectively in a consignment of 1,00,000 packets (e–0.2 =.9802)