Answer: 165.78 < μ < 180.22
Step-by-step explanation: <em>Confidence Interval of a mean</em> is a method to estimate the true population mean, i.e., we can get an interval where the true mean exists.
A confidence interval is calculated as
x ±
z is z-score for 99% confidence, which is: z = 2.58
Then, the estimate is
173 ±
173 ± 2.58*2.8
173 ± 7.224
lower limit: 173 - 7.224 = 165.78
upper limit: 173 + 7.224 = 180.22
The 99% confidence interval of the mean is between 165.78 and 180.22 and it means that the true mean of this population is between those numbers with 99% of confidence.