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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. Use this information and answer Question 4a to 4h.

Question 4a: What is the probability distribution of the life time of the motor, X?

Question 4b: In the first week, you were able to obtain 25 survey responses on the life of the motor you are studying. What is distribution of the average life of the motor, X ¯?

Question 4c: After a month-long survey, you collected 367 responses. What would be the expected value of the average life time of the motor using the survey responses?

Question 4d: After a month-long survey, you collect 367 responses. What is the probability that the average life time of the motor is greater than 10 years and 3 months? (Use four decimal places)

Question 4e: After a month-long survey, you collect 146 responses and find that the average life of the motor is 10.02 years. What is the upper limit of a two-sided 95% confidence interval of the true average life of the motor? (Use four decimal places)

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orchestra answered 1 year ago
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