Anchor: Case studies often use one or only a few instances, because collecting and analyzing comprehensive data are prohibitively difficult for large numbers of sites.
Entailed: Case studies are used because comprehensive data can be to large and difficult to use.
Contradiction: Case studies are used because they give comprehensive data.
Contradiction: A woman is running in the park with her walker.
Contradiction: The kid does a skateboarding trick.
Contradiction: Christopher's coworker is not a co-anchor.
Contradiction: A man has an outdoor shop.