what t test would I then use?

for the critical region if I read the chart right I got 1.860 as the value, so is the critical region? If the t test value is greater than or equal to 1.860, H0 is rejected? I'm confused because the only formulas in my book are for H0: p=p0

When I finally straighten the rest out can I use that same confidence interval formula ?

Thank you for helping me. It really means a lot to have someone willing to explain math to me.