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1-The marks obtained by a number of student in a certain subject are approximately normally distributed with a mean 70 and standard deviation 5. if 3

1-The marks obtained by a number of student in a certain subject are approximately normally distributed with a mean 70 and standard deviation 5. if 3 students are selected at random from this group what is probability that at least 1 of them would have scored above 75 marks?

2- The time (in hours) required to repair a machine is exponentially distributed with parameter λ if the probability that the repair time exceed 2 hours period is 0.3679, evaluate λ, hence find the probability of repair time to be at most 2 hours?

3- An engineer selects 10 components at random and it is reported that the average strength of the components is between 72.3 and 75.7 with 99% confidence. what is the mean and sample standard deviation of the 10 compov

or:1-The marks obtained by a number of student in a certain subject are approximately normally distributed with a mean 70 and standard deviation 5. if 3 students are selected at random from this group what is probability that at least 1 of them would have scored above 75 marks?2- The time (in hours) required to repair a machine is exponentially distributed with parameter \u03bb if the probability that the repair time exceed 2 hours period is 0.3679, evaluate \u03bb, hence find the probability of repair time to be at most 2 hours?3- An engineer selects 10 components at random and it is reported that the average strength of the components is between 72.3 and 75.7 with 99% confidence. what is the mean and sample standard deviation of the 10 compov

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