means of the signal and noise distributions, respectively, and σ
2
s
and σ
2
n
are
the variances of the signal and noise distributions respectively. It is obvious
that d′ is a statistical value after all. Accurate values of d′ will be obtained
to the extent that the values of d′ in the research sample approximate the
theoretical distributions (populations values) for the stimuli. Population
values are tenable when there are at least 50 observations for each particular
signal strength used in the experiment (Robertson & Morgan, ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month, and much more.