Answer:
The 95% confidence interval = [ 125.28, 148.52]
Explanation:
In a sample of 17 hip surgeries of a certain type, the sample mean surgery time was 136.9 minutes witha sample standard deviation s=22.6 minutes. Find a 95% confidence interval for the mean surgery time for this procedure. The CI is:____________
The formula for Confidence Interval =
Cl = Mean ± t × standard deviation/√n
We are using t score because our sample size is less than 30, hence it is small
Degrees of freedom = n - 1 = 17 - 1 = 16
T score for 95 % confidence interval = 2.120
CI = 136.9 ± 2.120 × 22.6/√17
CI = 136.9 ± 2.120 × 5.4813051258
CI = 136.9 ± 11.620366867
CI
= 136.9 - 11.620366867
= 125.27963313
≈ 125.28
136.9 + 11.620366867
= 148.52036687
≈ 148.52
The 95% confidence interval = [ 125.28, 148.52]