At the 5% significance level, can it be concluded that the correlation between daily sales and temperature is positive?

At the 5% significance level, can it be concluded that the correlation

between daily sales and temperature is positive? Formulate and test the

appropriate hypotheses. Use the critical value approach

So with this question, I used the test of hypotheses about p: but another class mate used the test of hypotheses about B,

Am I correct in my chosen formula as we are testing about the correlation between a+b or am I wrong in assuming this?

Thanks