The method of tree-ring dating gave the following years A.D. for an archaeological excavation site. Assume that the population ofxvalues has an approximately normal distribution.

1,2081, 2361, 2501, 3061, 2681, 3161, 2751, 3171, 275

The mean of this sample isx= 1272.33 and the standard deviation iss= 37.12.

(a) Find the critical t-value (t_c) for a 95% confidence interval.

________

(b) Find a 95% confidence interval for the mean of all tree-ring dates from this archaeological site.(Round your answers to the nearest whole number.)

Lower limit_______

upper limit__________