On average, people experience more anxiety for real spiders
(M = 5.00, SD = 1.65) than for pictured spiders (M = 3.75, SD = 1.91).
This difference, 1.25, 95% CI [0.53, 1.97], was significant
t(11) = 3.80, p = .003 and represents a medium effect, d = .65.
Calculating the effect size