Crawford Industries Purchases Step-Down Electrical Converters from Two Suppliers

question 29

Multiple Choice

Crawford Industries purchases step-down electrical converters from two suppliers.The converters from the two suppliers appear to have the same average life (measured in hours) but the variability in useful life appears be different for the units provided by the two suppliers.In random samples of 8 converters from supplier A and 8 converters from supplier B, the standard deviation in sample A was 40 hours; the standard deviation in sample B was 55 hours.Assume that converter life is normally distributed in each population.Test the null hypothesis that the population variance B is no greater than the population variancedeviation A, against the alternative hypothesis that the population variance B is greater than population variance A.Use a significance level of 5% for this one-tailed test and report the critical F (F_c) for the test.

• A)3.160
• B)6.013
• C)3.787
• D)2.965

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Definitions:

Prospective Studies

Research studies that follow participants over time to observe outcomes, such as the development of diseases, based on earlier exposures or risk factors.

Retrospective Studies

Research studies that analyze past data to assess outcomes and factors affecting them.

Evidence

Information or facts that help to establish the truth or validity of a belief, proposition, or phenomenon.

Longitudinal Design

A research design that involves repeated observations of the same variables or groups over a period of time, allowing for the study of changes and development.