machine produces bolts which are normally distributed with a mean of 4 mm and a variance of 0.09 mm. Bolts are measured accurately and any which are smaller than 3.5 mm or higher than 4.4 mm are rejected. Out of a batch of 500 bolts how many would be accepted?
machine produces bolts which are
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(a). (ii)..IQ test are measured on a scale which is normally distributed with a mean of 100 and a standard deviation of 15. A woman wants to form a society which only admits people with the top 1% of IQ scores. What would she have to set as the cut-off point in the test to allow this to happen?
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(a). (iii)..IQ test are measured on a scale which is normally distributed with a mean of 100 and a standard deviation of 15. A woman wants to form a society which only admits people with the top 5% of IQ scores. What would she have to set as the cut-off point in the test to allow this to happen?
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(b). A manufacturer doesn’t know the mean and Standard deviation of the ball bearings he is producing. However, a sieving system rejects all bearings larger than 2.4 cm and those under 1.8 cm in diameter. Out of 1000 ball bearings 8% are rejected as too small and 5.5% as too big. What is the mean and the standard deviation of the ball bearings produced?
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