A 90% Confidence Interval for the Average Salary of All

question 118

Multiple Choice

A 90% confidence interval for the average salary of all CEOs in the electronics industry was constructed using the results of a random survey of 45 CEOs. The interval was ($110,389, $128,192) .
Give a practical interpretation of the interval.

• A) We are 90% confident that the mean salary of all CEOs in the electronics industry falls in the interval $110,389 to $128,192.
• B) 90% of all CEOs in the electronics industry have salaries that fall between $110,389 to $128,192.
• C) 90% of the sampled CEOs have salaries that fell in the interval $110,389 to $128,192.
• D) We are 90% confident that the mean salary of the sampled CEOs falls in the interval $110,389 to $128,192.

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Definitions:

Induction Motors

A type of electric motor that operates on the principle of electromagnetic induction, where the rotation of the motor is caused without direct electrical connection to the rotor.

Variable-frequency Drive

A system used to control the speed of an electric motor by varying the frequency and voltage supplied to the electric device.

Motor Controller

A device that regulates the performance of an electric motor by varying parameters such as voltage and current.

PWM

Pulse Width Modulation, a technique used to control the amount of power delivered to an electrical device by varying the duty cycle of a pulse signal.