PSY 303 Lecture Notes - Lecture 4: Birthday Cake, Carrot Cake, Random Assignment
Document Summary
Control groups provide a basis for comparison. Ex: comparing the presence of x with the absence of y. Sometimes you need to control multiple variables. Sometimes a true control group (ex: complete absence of manipulation) is unnecessary. Ex: comparing political candidates republican vs democrat. Ex: comparing target gender male vs female vs unspecified. One groups gets birthday cake, one group gets nothing to eat, one group gets sandwich. Cake vs non sugary food vs no food. Racist jokes vs non racist jokes vs no joke or racist joke vs racist statement: manipulating an independent variable. Quasi experiments that use existing subject variables rather than manipulated independent variable: unbiased assignment to condition comparing the effects of different conditions is meaningful only if the subjects in ea(cid:272)h (cid:272)o(cid:374)ditio(cid:374) (cid:449)e(cid:396)e(cid:374)(cid:859)t al(cid:396)eady diffe(cid:396)e(cid:374)t f(cid:396)o(cid:373) the sta(cid:396)t. If offer chocolate to the whole class and compared happiness of those who chose chocolate vs those who declined.
