A Manufacturer Claims That a Certain Brand of VCR Player

question 41

Essay

A manufacturer claims that a certain brand of VCR player has an average life expectancy of 5 years and 6 months with a standard deviation of 1 year and 6 months. Assume that the life expectancy is normally distributed.
(a)Selecting one VCR player from this brand at random, calculate the probability of its life expectancy exceeding 7 years.
(b)The Critical Consumer magazine decides to test fifty VCRs of this brand. The average life in this sample is 6 years and the sample standard deviation is 2 years. Calculate a 99% confidence interval for the average life.
(c)How many more VCRs would the magazine have to test in order to halve the width of the confidence interval?

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Definitions:

Identity Theft

Identity theft is the fraudulent acquisition and use of someone's private identifying information, typically for financial gain.

FTC

Stands for the Federal Trade Commission, a U.S. federal agency tasked with protecting consumers and maintaining competition.

Cosign

To sign a legal document alongside another person, taking joint responsibility for the obligation the document entails, such as a loan.

Equal Credit Opportunity Act

A U.S. federal law designed to ensure that all consumers have an equal chance to obtain credit, prohibiting discrimination.