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A machine produces steel nails whose lengths are normally distributed with a mean of 25 mm and a standard deviation of 0
Posted: Thu Apr 28, 2022 7:21 am
by answerhappygod
- A Machine Produces Steel Nails Whose Lengths Are Normally Distributed With A Mean Of 25 Mm And A Standard Deviation Of 0 1 (37.75 KiB) Viewed 41 times
A machine produces steel nails whose lengths are normally distributed with a mean of 25 mm and a standard deviation of 0.4 mm. A steel nail is acceptable if its length is between 24.4 mm and 25.4 mm. (a) If a steel nail is selected at random, what is the probability that it is acceptable? [5 marks] (b) If 15 steel nails are selected at random, what is the probability that more than 12 are acceptable? [4 marks] (c) Suppose that 200 steel nails are selected at random. Use normal approximation to binomial to find the probability that at least 80% of them are acceptable. [8 marks] (d) If 10 steel nails are selected at random, what is the probability that the mean length of the sample is less than 25.2 mm? [4 marks]