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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.

1,299

1,194

1,201

1,285

1,268

1,316

1,275

1,317

1,275

(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 four decimal places.)

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 sample mean = 1270

Sample Standard Deviation = 44.7

Confidence Interval is (1242, 1298)

I used a TI-84 calculator, input the data, under STATS in L₁

I ran STAT, Calc, 1-Var Stats to get the sample mean and sample standard deviation

For the Confidence Interval I used STAT, Test, T-Interval, Data and input 90% for the Confidence Level (use T-Interval since you don't have the population standard deviation).