Help with setting my study!

Hi all,
I'm a newbie to biostatistics and I'm trying to figure out how to set the statistical part of my final project.
I'm a dentistry student and I picked up a project about the assessment of human skeletal growth basing on the radio graphic analysis of cervical vertebrae
I'll have a sample of radiographs to analyze (for each subject I have one radiograph showing cervical vertebrae and one radiograph showing another part of the body, which is considered the golden standard for assessing skeletal growth)

I'm considering these 3 methods:
- qualitative analysis basing on morphological criteria of the vertebra. Information is classified in stages (I though V)
- quantitative analysis method based on the calculation of a regression formula that uses chronological age of the patient as dependent variable and 3 ratio measurements as independent variables (the ratios are obtained by a combination of the measurements of anterior vertebral height, posterior vertebral height and vertebral length)
- quantitative analysis method based on an angular measurement. Also subdivided in stages (angular ranges, e.g. Stage I -> 0 to 6 degrees, etc.)

The reference method to compare these methods with is another one based on the radio graphic assessment of another part of the body, as previously said. Stages (I through XI).

So basically I need to:
- compare each one of them with the reference method I just mentioned and say how much they deviate from this golden standard method. How can I do that? How should I consider the results obtained by stages and those obtained by the regression formula(exact age assessment and not stages)?

- how can I compare the skeletal age with chronological age (they are known to have huge variation)? Do you think would be significant comparing the skeletal age assessed by the reference method compared with the chronological age, get a statistical value ( no clue of which one), and compare it 3 different Times with the values obtained by comparing each one of the three analysed methods with the reference method?
I basically need to say how much the skeletal age of each one of these methods deviates from the chronological age, and I don't understand what I need to compare..

I spare you from the other 250 questions I have about sexual dimorphism,etc.:D

From my statically poor language you probably understand which my level of preparation about the subject is, we've never been though biostatistics during the degree and on my own I'm having really great difficulties carrying out this project. Plus the university is being 0 helpful in providing a tutor that knows about biostatistics

I hope you guys can help me starting from somewhere, I like to work hard but need a little help starting since this subject is one of thoughest ones when it comes to scientific research

Have a nice day!