#confidence-interval

Question 1: Select all that apply

From a simple random sample of 64 emergency-room patients, a hospital computes a 95% confidence interval of (128, 147) minutes for the mean waiting time, using the normal model for the sample mean. Which statements are true? Select all that apply.

We are 95% confident that the mean waiting time of all patients at this ER is between 128 and 147 minutes.1
The sample mean is 137.5 minutes and the margin of error is 9.5 minutes.2
95% of random samples of 64 patients would have a sample mean between 128 and 147 minutes.3
Halving the margin of error would require doubling the sample size.4

#confidence-interval

Timed test