statistical theory

hi guys am taking a course on statistical theory with the folowing
topics :

- discrete and continous random variable
- probability density function of random variable
- expected value of continous random variable
- moment generating function
- conditional distibution

please i am finding them difficult to understand even though i attended
classes, i would therefore request that if anyone that can point me to
books or websites that deal with the above topics from a novice point
of view (a dummy point of view of which i am one), i will be most
grateful for such an offer. or can take me on online training

thanks a zillion to all.

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