When stoner (1961) compared the average decision of a group's individual members against their group decision generated through group discussion, he found that?

I beleive the answer is:  groups arrived at riskier decisions than individuals.

According to stoner, there are several factors that could influence risky decisions when it's initiated in a group setting compared to when an individual is alone.
For example, group members might felt the fear of outcasted by the members of the group if they refuse to conform to the risk decision/