Assuming a two-tailed test with α=0.50, how large a correlation is needed to be statistically significant for each of the following samples?
a. A sample of n = 15 individuals

work done:

(r*sqrt{15-2}) / sqrt{1-r^2} = t*

where t* is the proper t value with 13 degrees of freedom.

then

(r*sqrt{15-2}) / sqrt{1-r^2} = 1.9, and when we solve for "r"...

r/sqrt{1-r^2} = 1.9*sqrt{13}, square both sides to get:

r^2/(1-r^2) = 1.9^2 / 13

I'm not sure what the correct answer is and don't even think of work is right... can someone guide me on this so I can arrive at the correct solution so I can do more practice problems please? Thanks.