Question

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. 1271 1187 1194 1250 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.)

Answer 1

Answer:

The sample mean year is 1261 A.D.

The standard standard deviation is of 46 A.D.

Step-by-step explanation:

Sample mean:

Sum of all values divided by the number of values. So

$x = \frac{1271+1187+1194+1250+1268+1316+1275+1317+1275}{9} = 1261.4$

Rounding to the nearest whole number, the sample mean year is 1261 A.D.

Sample standard deviation:

Square root of the sum of the difference squared between each value and the mean, divided by one less than the sample size. So

$s = \sqrt{\frac{(1271-1261.4)^2+(1187-1261.4)^2+(1194-1261.4)^2+(1250-1261.4)^2+(1268-1261.4)^2+(1316-1261.4)^2+(1275-1261.4)^2+(1317-1261.4)^2+(1275-1261.4)^2}{8}} = 45.8$

Rounding to the nearest whole number, the standard standard deviation year is of 46 A.D.