[R] Significance of slopes

[Christian Arnold]

Hello R community,

I have a question regarding correlation and regression analysis. I have 
two variables, x and y. Both have a standard deviation of 1; thus, 
correlation and slope from the linear regression (which also must have 
an intercept of zero) are equal.
I want to probe two particular questions:
1) Is the slope significantly different from zero? This should be easy 
with the lm function, as the p-value should reflect exactly that 
question. If I am wrong, lease correct me.
2) Is the slope significantly different from a non-zero value (e.g. 
0.5)? How can I probe that hypothesis? Any ideas?

I apologize if this question is too trivial and already answered 
somewhere, but I did not find it.

Thank you for the help!
Christian