**Answer:**

The 99% confidence interval of the population mean for the weights of adult elephants is between 12,475 pounds and 12,637 pounds.

**Step-by-step explanation:**

We have the standard deviation for the sample, so we use the t-distribution to solve this question.

The** first step** to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 10 - 1 = 9

**99% confidence interval**

Now, we have to find a value of T, which is found looking at the t table, with 9 degrees of freedom(y-axis) and a confidence level of . So we have T = 3.25

**The margin of error is:**

M = T*s = 3.25*25 = 81

In which s is the standard deviation of the sample.

The **lower end** of the interval is the sample mean subtracted by M. So it is 12,556 - 81 = 12,475 pounds

The **upper end** of the interval is the sample mean added to M. So it is 12,556 + 81 = 12,637 pounds.

The 99% confidence interval of the population mean for the weights of adult elephants is between 12,475 pounds and 12,637 pounds.