Question

The technology underlying hip replacements has changed as these operations have become more popular (over 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 ofsqueaking. An article reported that in one study of 143 individuals who received ceramic hips between 2003 and 2005, 12 of the hips developed squeaking.

(a) Calculate a lower confidence bound at the 95% confidence level for the true proportion of such hips that develop squeaking. (Round your answer to three decimal places.)

Answer 1

hope it help

Answer 2

The solution for this problem is found in the Devore textbook, 8th and 9th edition, equation 7.10. Use Z=1.645 instead of Z=1.96. For the +/- use only the - (minus). Its the long form quadradic equation.