(A) Construct a 95% Confidence Interval for the Average Width

question 8

Essay

(A) Construct a 95% confidence interval for the average width of an elevator rail. Do we need to assume that the width of elevator rails follows a normal distribution?
(B) How large a sample of elevator rails would we have to measure to ensure that we could estimate, with 95% confidence, the average diameter of an elevator rail within 0.01 inch?

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Definitions:

Survey Method

A research technique that involves collecting data from a sample of individuals through their responses to questions.

Questionnaires

A research instrument consisting of a series of questions for the purpose of gathering information from respondents, often used in surveys and studies.

Interviews

A method of collecting information through direct conversation, typically used for research or employment selection purposes.

Experimental Research Method

A research methodology that tests hypotheses and establishes cause-effect relationships by manipulating independent variables and observing their effects on dependent variables.