Where can I find statistical studies related to psychology online, or what book would I be able to find this in?

For my college statistics class, I must find a statistical study related to my major (psychology) and break it down by listing what the population is, what the sample population is, what the parameters of interest are, etc.

However, all of the statistics I am finding are very vague. An example: 2.1 million people, or 1% of the population has schizophrenia. With this statement alone, I cannot tell how big the sample size was, etc.

Does anyone know where I can get a DETAILED report of a statistical observation related to psychology?