And if you determine that Ha =/= 0, it becomes a two-tailed test, so you have to divide the alpha by 2 when finding the rejection zone, or also multiply the P-value by two, right?

I'll give an example from some questions that I have to answer for a homework:

1) Given the following statistics of a multiple regression model, can we conclude at the 1% significance level that X1 and y are linearly related?

2) Test at the 5% significance level to determine whether annual household income and annual family clothes expenditure are positively linearly related.

3) Test at the 1% significance level to determine whether the number of family members and annual family clothes expenditure are linearly related.

Thank you very much!