2464 women (unselected) undergoing mammography were administered the RST. Is this sample a cross-sectional or not? I think women at the clinic for mammography make up a cohort (of at-risk women) that may not be representative of the larger population.
Please advise.
You may assume that the 2464 women represent the population in whom we are interested and the random samples of 86 RST -positive and 210 RST-negative women are representative of those particular groups. This is not a cohort study; this is a cross-sectional study of test accuracy.
