Many studies have been done about how music affects blood pressure and heart rate. What your conclusion states is pretty accurate and relatable; whether your blood pressure lowers or raises can significantly be based on if you simply enjoy the music or not. Usually people think that classical music is slow and will soothe someone and rap is fast paced and will excite people. This is partially true because if you make someone who listens to classical music all time listen to rap, you would probably see a drastic increase in heart rate or bp. If you make someone listen to rap who listens to it all the time, the increase will not be as drastic or may be nonexistent. Yes, classical music soothes and rap can excite, but that doesn't have to happen to every person.

As far as your experiment goes, it is really important for a science experiment like this you state in your conclusion whether your hypothesis was accurate or not. Also, your results may vary depending on who you chose as your participants. It is important to have a good, random sample of participants with different age ranges and music choices. Your results will be more significant if you have more people to experiment on and if you keep the music you're going to play a complete secret to them, so you really know what happens to their blood pressure and heart rate as soon as that particular music is played. One method you can try is to make a 5 minute recording with your four genres of music in a random order so the participant won't know what he or she is expecting and you will be able to see the drastic changes in their blood pressure and heart beat. You can also research some other studies like yours and compare your results to see how they are similar or different to other scientists' results (don't change your results!). Good luck on the rest of your experiment!