The method of tree ring dating gave the following years A.D. for an archaeological excavation site. Assume that the population of x values has an approximately normal distribution. 1257 1201 1180 1208 1268 1316 1275 1317 1275 (a) Use a calculator with mean and standard deviation keys to find the sample mean year x and sample standard deviation s. (Round your answers to the nearest whole number.) x = A.D. s = yr

Equation: or

Solution:

Step-by-step explanation:

The formula that is used to calculate the perimeter of  a square is:

Where "s" is the side lenght the square.

Knowing that Xin used  20 yards of fencing to build the walls of a square chicken coop (in which the lenght in yards of each wall is represented with "x"), you can identify that:

Then, you can susbtitute values into the formula :

Finally, you must solve for "x" in order to find its value.

This is: