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.

1194

1306

1194

1313

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

1194	-79.11	6258.3921
1306	32.89	1081.7521
1194	-79.11	6258.3921
1313	39.89	1591.2121
1268	-5.11	26.1121
1316	42.89	1839.5521
1275	1.89	3.5721
1317	43.89	1926.3321
1275	1.89	3.5721

Refer t-table or use excel function "=T.INV.2T(0.10,8)" to find the critical value of t.