 Hi, this is Dr. Don. I have a problem out of Chapter 6 about confidence intervals. Here we're asked to construct the indicated confidence interval for the population mean using a T distribution. We're given the data here, summary data. The confidence level we want is 0.99. The mean of the sample X bar is 1.15. The standard deviation of the sample S is 10 and the sample size N is 16. Just a clue, when you're looking at these things, sometimes they won't tell you which distribution to use and you need to look for clues. The first clue I always look for is the standard deviation. Is it sigma, the population standard deviation? If so, that would push me to use the Z distribution, the normal distribution. If N is less than 30, that would push me to use the T distribution. And here we're given S, which is the sample standard deviation. So that confirms that I should use the T distribution, which is what they've asked for. Remember up here in question help, if you click on that, you can get the stat crunch. So let's open up stat crunch. Just like many problems, we start with stat and this is a T stat. We have one sample and we've got summary data and we just bring that up. We type in our mean of 115, our standard deviation of the sample of 10, sample size of 16. We click on confidence interval for the mean. We put in our confidence level of 0.99 and we're going to click compute. And we get our results there, lower limit of 107 and that rounds to 0.6. We're looking at one decimal place and 122.4 for the upper limit. So I hope this helps.