If I count correctly you have 8 answered questions and 5 unanswered, which is about average (we have almost 33K unanswered questions of a bit over 82K asked, so if that applied to you, you'd expect about 8 questions answered of 13). Many of your tags correspond to areas with low answer rates - questions with a tag like "kernel smoothing" only seems to get answered about 40% of the time for example (and some of your other tags fare worse than that), but you have a pretty good hit rate for the kernel-smoothing tag by comparison to the general proportion.
General points about the site as a whole:
Note that there has been strong growth over time in the number of questions posted, including many more questions of poor quality requiring effort in one form or other from the same people who answer a lot of the questions -- the growth in the number of answers posted is much more modest, and the lower quality of questions compounds the problem (more time is being taken up with "janitorial" tasks).
This means that fewer questions are answered over time, a trend that has continued for several years now. We close more than we used to but the more we do that the fewer we'll answer. There's no clear solution outside of trying to attract more people willing to answer questions (as well as to help with the tasks of keeping the site running in other ways).
In addition, because of limited time to answer questions, I tend to choose ones that are easier to understand first, or about which I think there's something important to say (so I tend to avoid questions that look close to well-trodden territory even if it's not an exact duplicate unless it's really focused or otherwise gives scope to say something that seems interesting). On top of all that, if a question will involve an hour of research or a similar amount of time explaining a sequence of issues, it's likely to push out all my other on site activity for the day -- and still might not produce an answer.
Some specific comments relating to your questions:
Broadly, many of your questions strike me as taking an "odd" or idiosyncratic point of view, and that means -- even when they're not actually hard -- they often involve quite a bit of untangling or clarification to answer. I sometimes find myself saying "huh? maybe come back to this one".
In about half of the questions of yours I have read I have an intent to come back and see if I can attempt an answer but I often don't -- there's often fifty or a hundred other questions posted before I finish looking through the last 24 hours of posts. I imagine that some other people will have similar issues.
There are also a lot of your questions I really don't think I can give a good answer to -- sometimes they're outside the areas I know much about, for example.
What can you do about it? Try to be as focused/specific, clear, and well researched as you can; some questions might be broken into two shorter questions. Definitely try to read some books and or notes related to what you're interested in - reading widely will help frame your questions better (as well as improving your general understanding). Don't be afraid to come back and edit a question as you get more of a handle on it, and don't be afraid to post an answer yourself -- if it's less than ideal, people may offer brief comments where they wouldn't have time to answer it themselves.
Where you can, try to avoid broad or unfocused questions.
I think some of the questions you post are pretty good / take an interesting line and I would encourage you to keep posting.
self-studycan include self-learning if you're doing "routine bookwork". $\endgroup$