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.

1229

1236

1271

1229

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.)

(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:

upper limit:

Answer 1

mean = x = 1268.44

s.d.= s= 33.3096

b)

Mean (\bar{x}) = 1268.44

Sample size (n) = 9

Standard deviation (s) = 33.3096

Confidence interval(in %) = 90

t = 2.306

Since we know that

Required confidence interval =

Required confidence interval = (1268.44-25.604, 1268.44+25.604)

Required confidence interval = (1242.836, 1294.044)