Part 2

Research question: we are interested in studying the association between the age of the felled tree and wood species in the population under consideration. Please complete the following tables, calculating the values of A and B.

Observed count | 1 (less than 15) | 2 (16-21) | 3 (22-26) | 4 (more than 26) | Sum blackwood | A=*** | 10 | 11 | 14 | 46 sassafras | 17 | 22 | 15 | 15 | 69 Sum | 28 | 32 | 26 | 29 | 115

Expected count | 1 (less than 15) | 2 (16-21) | 3 (22-26) | 4 (more than 26) blackwood | 11.2 | 12.8 | 10.4 | 11.6 sassafras | 16.8 | B=*** | 15.6 | 17.4

chi-squared | 1 (less than 15) | 2 (16-21) | 3 (22-26) | 4 (more than 26) blackwood | 0.004 | 0.613 | 0.035 | 0.497 sassafras | 0.002 | 0.408 | 0.023 | 0.331

A [integer]:

Answer 6 Question 1

B [use at least 3dp]:

Answer 7 Question 1

A chi-squared test of independence is run to answer the research question. Consider the output of the test below, and answer the questions:

Pearson's Chi-squared test

data: table(var1, var4) X-squared = 1.9121, df = 3, p-value = 0.5909

What is the null hypothesis? Choose one among the following options:

a. the age of tree is associated with wood species

b. the age of tree felled at a specialty timber plantation is not distributed according to the given table of probabilities

c. the age of tree and wood species are independent

d. the age of tree felled at a specialty timber plantation is distributed according to the given table of probabilities

Answer 8 Question 1 abcd

From the p-value as reported above, we can conclude that the decision of the test is:

Answer 9 Question 1 Accept H0Reject H0Do not accept H0Do not reject H0

What is the conclusion of the test?

a. There is not enough evidence that the age of tree felled at a specialty timber plantation is distributed differently than the given table of probabilities

b. There is evidence that the age of tree felled at a specialty timber plantation is distributed according to the given table of probabilities

c. There is not evidence that the age of tree and wood species are associated

d. There is evidence that the age of tree and wood species are independent

e. There is evidence that the age of tree felled at a specialty timber plantation is not distributed according to the given table of probabilities

f. There is evidence that the age of tree and wood species are associated

g. There is evidence that the age of tree felled at a specialty timber plantation is not distributed according to the given table of probabilities

Answer 10 Question 1 abcdefg