In a random sample of 68 children, the mean age at which they first began to combine words was 16.9 months, with a standard deviation of 1.8 months. Construct a 99% confidence interval for the mean age at which all children begin to combine words.

1. Which parameter(s) are you given? Mark all that apply.
   • p
   • $\displaystyle \mu$
   • $\displaystyle \sigma$
   • none
2. Which statistic(s) are you given? Mark all that apply.
   • $\displaystyle \overline{{x}}$
   • $\displaystyle \hat{{p}}$
   • $\displaystyle \hat{{q}}$
   • s
   • x
   • none
3. What is the problem asking you to do?
   • Estimate a parameter
   • Test a given parameter
4. Which function in your calculator should you use to solve the problem?
   • 1-PropZInt
   • 1-PropZTest
   • ZInterval
   • Z-Test
   • TInterval
   • T-Test
   • invNorm