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In: Statistics and Probability

The average life of a certain type of motor is 10 years with a standard deviation...

The average life of a certain type of motor is 10 years with a standard deviation of 2 years. You are interested in measuring the life time of this motor by conducting a survey asking customers’ experiences.

a.) After a month-long survey, you collect 146 responses. What is the probability that the average life time of the motor is greater than 10 years and 6 months?

b.) After a month-long survey, you collect 367 responses and find that the average life of the motor is 10.12 years. What is the upper limit of a two-sided 95% confidence interval of the true average life of the motor?

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orchestra answered 2 years ago
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