There's a lot of text there which you may ignore. I just posted it all for background if needed. I'm having issues with parts $(c)$ and $(d)$. I don't understand how knowing the population mean would influence hypothesis testing for the mean.
Just for a bit of background, hypothesis tests for the mean were done for $200$ different samples and the p values were recorded. And $29.5%$ of these values were less than $0.1$, in other words reject the null hypothesis below
