Comparing data sets HW

I am having trouble with the third problem on this homework:

"You wish to test the following claim (Ha) at a significance level of α=0.01. For the context of this problem, μd=μ2−μ1 where the first data set represents a pre-test and the second data set represents a post-test.

  Ho:μd=0
  Ha:μd≠0

You believe the population of difference scores is normally distributed, but you do not know the standard deviation. You obtain pre-test and post-test samples for n=87 subjects. The average difference (post - pre) is ¯d=5.5 with a standard deviation of the differences of sd=15.6."

I am not sure how I am supposed to compute the test statistic when only given this information.

Any help would be greatly appreciated

So when you are looking at this problem you have to use past knowledge that we have used to find the correct answer. Take another look at the three variables that you DO have. You have a sample size n = 87 a mean of d = 5.5 and a sigma = 15.6. Look back a little bit on the notes but, one hint for the critical value is to use R-Studio and that command is:

qt(Significant value, df) -----> qt(0.01, 86)

If you still need help in like an hour or so write on this again and ill help you with the rest of it.