A lifelong forest resident claims that the average age of trees is 20 years, but you believe it is older than that. In order to test this, you take a sample of 10 trees. The computed value of the sample average is 21.5 years. The underlying distribution of tree ages is assumed to be normal and standard deviation of tree ages is known to be 3 years of age based on historical data. After doing some calculations, you find that the test statistic is 1.5811.

What is the p-value of this test? Perform this test at a= 0.01

(21.5-200/3/ sq rt 10)= 1.5811

answer:

how did they get 0.057