Question

[Statistics] Given the mean of a sample and sample size calculate a lower confidence bound at the 95% confidence level for the true value

Answer 1

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 of squeaking. An article reported that in one study of 152 individuals who received ceramic hips between 2003 and 2005, 11 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

Answer 2

11/152 - 1.645*sqrt((11/152(1-11/152))/152)

= 0.038

Answer 3

most likely webassign is wrong

Answer 4

Alright then, thank you.