The t-interval for a mean Problem set B Answers

\(6.48 < \mu < 7.47\) cm

\(210 < \mu < 249\) ml

\(15.0 < \mu < 16.4\) minutes

\(120 < \mu < 136\) mm Hg

\(26.2 < \mu < 28.3\) cm; 1.04 is the margin of error

1. (a) Assume the times are normally distributed (the t-interval needs this).
2. (b) \(12.0 < \mu < 13.4\) seconds

1. (a) \(7.45 < \mu < 8.35\) hours
2. (b) \(\mu\) is between the two ends: we are 95% confident

1. (a) 2
2. (b) 92%, close to 90%
3. (c) The method gives an interval containing the true mean 90% of the time over many samples. This one interval either contains \(\mu\) or does not.

1. (a) 21.0
2. (b) 2.40
3. (c) 3.78