The human development index is just a statistic of a country that takes a lot of things into account. For example life expectancy, education and income. I don't know if there are other things that are also taken into account.
Rural deprivation just means that there's a lack of material benefits which are basic necessities in a rural area.
I presume you're doing Edexcel Unit 2, I took that exam in January so if you need any help feel free to inbox me :)