The t-interval for a mean Problem set A Answers

\(14.1 < \mu < 16.7\) minutes

\(98.4 < \mu < 118\) g

\(8.04 < \mu < 8.36\) kg

\(68.2 < \mu < 80.4\) beats per minute

\(3.78 < \mu < 4.47\) m; 0.345 is the margin of error

1. (a) Assume the speeds are normally distributed (the t-interval needs this).
2. (b) \(45.5 < \mu < 55.6\) km/h

1. (a) \(22.4 < \mu < 24.8\) hours
2. (b) \(\mu\) is between the two ends: we are 95% confident

1. (a) 3
2. (b) 88%, 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) 44.0
2. (b) 2.80
3. (c) 5.06