In a fictitious study, 100 out of 1000 people aged 60 years and over were positive in detecting breast cancer using Tumour Biopsy (gold standard). Using mammography, 90 of breast cancer patients and 135 healthy persons were also positive by this test.

(I) Calculate and interpret the sensitivity of mammography. (II) Calculate and interpret the specificity of mammography.
(III) Calculate and interpret the positive predictive value of mammography.
(IV) Calculate and interpret the negative predictive value of mammography.

i am having really hard time trying to interpret this