In a 4 × 3 factorial design, for a completely independent groups design with 10 participants per group, how many participants are needed?

A) 120
B) 30
C) 70
D) 60

In a 4x3 factorial design, there are four levels of one independent variable and three levels of the other independent variable. To calculate the number of participants needed, we multiply the number of levels for each independent variable and then multiply by the number of participants per group. So, for this design, the total number of participants needed would be:

4 x 3 x 10 = 120