Final answer:
The study described is best conducted using a Two-Way Factorial Design, which assesses the combined and individual effects of gender and social class on IQ scores, as it involves two independent variables.
Step-by-step explanation:
The correct option is A:
The appropriate type of study design for examining the effects of gender and social class on IQ scores is a Two-Way Factorial Design. This design will allow the researcher to analyze how two independent variables, gender and social class, separately and together influence the dependent variable, which in this case, are the IQ scores. This type of design is called a Two-Way Factorial Design. The researcher would collect data from participants belonging to different gender groups (male/female) and social class groups (low, middle, and upper) to analyze the effects on IQ scores.
A One-Way ANOVA is used when there is only one independent variable, but since there are two different variables (gender and social class), it is not the right choice for this study. A Three-Way Factorial Design would involve three independent variables, which we do not have in this scenario. A Correlational Design is generally used to assess the relationship between two continuous variables, not categorically distinct ones like gender and social class.