Question

4. A researcher notes that male-female pairs of fraternal twins share a similar

environment in a mothers' womb. This exposes the female twin to higher
levels of the hormone testosterone during prenatal development. This
hormone is thought to be responsible for masculinizing the brain (it leads to
male-typical behaviors). Likewise, the male twin is exposed to higher levels
of the hormone estrogen. This hormone is thought to be responsible for
feminizing the brain (it leads to female-typical behaviors). To test whether
exposure to testosterone and estrogen may influence male and female typical
behavior, the researcher selected a sample of female-male fraternal twins and
compared them to identical twins of each gender (male, female). She measured
tendencies toward aggression using an aggression assessment where higher
scores indicated greater aggression (a male-typical trait). It was hypothesized
that if hormone exposure influenced behavior, then aggression scores will vary
among the groups.

Dependent variable:
Factor A:
Levels of Factor A:

Factor B:
Levels of Factor B:
Number of groups:

Answer 1

Answer: The dependent variable in this study is tendencies toward aggression, as measured by the aggression assessment.

Factor A is the gender of the twin, with two levels: female and male.

Factor B is the type of twin, with two levels: fraternal and identical.

The number of groups being compared in this study is four: female-male fraternal twins, female identical twins, male identical twins, and male-female fraternal twins.