The technology underlying hip replacements has changed as these operations have become more popular (more than 250,000 in the United States in 2008). Starting in 2003, highly durable ceramic hips were marketed. Unfortunately, for too many patients the increased durability has been counterbalanced by an increased incidence of squeaking. The May 11, 2008 issue of The New YorkTimes reported that in one study of 143 individuals who received ceramic hips between 2003 and2005, 10 developed squeaking problems. a. Calculate a lower confidence bound at the 95% confidence level for the true proportion of suchhips that develop squeaking. b. Interpret the 95% confidence level used in part (a).

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