The mean age of De Anza College students in a previous term was
26.6 years old. An instructor thinks the mean age for online
students is older than 26.6. She randomly
surveys 59 online students and finds that the sample mean
is 29.9 with a standard deviation of 2.1. Conduct a
hypothesis test at the 5% level.
Note: If you are using a Student's t-distribution
for the problem, you may assume that the underlying population is
normally distributed. (In general, you must first prove that
assumption, though.)
Construct a 95% confidence interval for the true mean. Sketch
the graph of the situation. Label the point estimate and the lower
and upper bounds of the confidence interval. (Round your answers to
two decimal places.)