Determining the truth value of a statement I am stuck with the following question,

Determine the truth value of each of the following statments(a
  statement is a sentence that evaluates to either true or false but you
  can not be indecisive).
If 2 is even then New York has a large population.

Now I don't get what does truth value means here. I would be thankful if someone could help me out. 
Thanks in advance.

If X Then Y is an implication. In other words, the truth of X implies the truth of Y. The "implies" operator is defined in exactly this manner. Google "implies operator truth table" to see the definition for every combination of values. Most importantly, think about why it's defined in this manner by substituting in place of X and Y statements that you know to be either true or false.
One easy way to summarise the definition, is that either X is false (in which case it doesn't matter what the second value is), or Y is true.
So applying this to your statement: 2 is indeed even (so now that X is true we only need to check that Y is true to conclude that the implication is indeed valid). NY does indeed have a large population, and so we conclude that the implication is valid, and the sentence as a whole is true!
