The study by Baron-Cohen et al. (eyes test) used several samples of participants, selected in different ways. One of these was a volunteer sample.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.

1. [2] 1 mark for a (brief) generic description of how a volunteer sample is obtained 1 mark for reference to how this was done in this study, i.e. link a self-selecting sample = 1 mark (generic) a group of people who opt in to the study/who choose to participate = 1 mark (generic) participants who respond to a request to be in the study from the researcher = 1 mark (generic) Baron-Cohen et al. recruited some participants using adverts in the Autistic Society magazine/through Autism support groups = 1 mark (linked)
2. [2] 1 mark for advantage (generic or linked) 1 mark for disadvantage (generic or linked) Advantage: Easy to obtain sample as they come to the researcher (opt in) = 1 mark Low drop-out rate = 1 mark No selection bias by experimenter = 1 mark Disadvantage: May all be similar people/not representative/cannot generalise from them = 1 mark May be more 'keen,' e.g. try harder on eyes test than autistics would generally = 1 mark