In general the diameter of a tree trunk increases with age what could be the correlation between diameter of the tree trunk and age for all trees -0.7 0 0.7 1

The answer is C I just took this quiz :)

Option c) 0.7

Step-by-step explanation:

We are given in the question that there is a direct relationship between the tree trunk and the the age of the tree.

Correlation helps us to study relationship between two variables. A negative correlation means that there is inverse relation between variables and a positive value of correlation means that there is a direct relation.

a) -0.7

This could not define the correlation between the tree trunk and age of tree as a negative correlation means inverse relation which is not in this case.

b) 0

This again cannot be used to describe the correlation because a correlation means that there is no relation in the variables, which is not true in the case of tree trunk and age of tree

c) 0.7

Yes, this can be used to describe the relation correlation of the tree trunk and age of tree.  A correlation f 0.7 means that as the age is increasing so is the diameter of the tree trunk is increasing.

d) 1

A correlation of 1 means a perfect relationship. That is the line of best fit completely covers the data completely. The value of one variable increases linearly with the second variable which is not possible in real life case of diameter of tree trunk and the age of tree.