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.

1250

1271

1285

1320

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

(b) Find a 90% confidence interval for the mean of all tree ring dates from this archaeological site. (Round your answers to the nearest whole number.)

lower limit	A.D.
upper limit	A.D.

Answer 1

The statistical software output for this problem is:

One sample T confidence interval: : Mean of variable 90% confidence interval results: Variable Sample Mean Std. Err. DF L. Limit U. Limit Data 1286.3333 8.419554 8 1270.6768 1301.9899

Hence,

a) x = 1286

s = 25

b) 90% confidence interval:

Lower limit = 1271

Upper limit = 1302