The given information we have is:
significance level alfa=0.01
n=171
d=6.1
sd=39.8
To find the test statistic for this sample, let's calculate the z-score:
![\begin{gathered} Z=\frac{\bar{d}-\mu_d}{\sigma/\sqrt[]{n}} \\ Z=\frac{6.1-0}{39.8/\sqrt[]{171}} \\ Z=2.004 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/rtjpx3bztpx3mggnla0wxwrdbizeydsb91.png)
The test statistic is 2.004.
The p-value has to be calculated as a two-tailed test, since the hypothesis Ha is ud is different to 0, which means can be greater or less than 0.
p-value for two tailed test is given by:

The p-value is 0.0451
The p-value is greater than alfa since 0.0451>0.01