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:

Joseph McCarthy

An American politician who served as a U.S. Senator from Wisconsin and is best known for his anti-communist activities and the resulting "McCarthyism" during the early 1950s.

Voting Rights Act

A landmark piece of federal legislation in the United States that prohibits racial discrimination in voting.

1965

A significant year marked by events like the passage of the Voting Rights Act in the United States, aimed at overcoming legal barriers at the state and local levels that prevented African Americans from exercising their right to vote.

Establishment Clause

A provision within the First Amendment of the U.S. Constitution that prohibits the government from establishing an official religion or unduly favoring one religion over another.