During a study testing a new vaccine drug for Zika virus the research team grouped volunteers enrolled for the test into Group A and Group B Group A received an inert drug (placebo) while group B received the vaccine. What is the experimental factor

b

idk

step-by-step explanation:

payback

there is only one way to arrange all the eight relative to each other because they are not distinct. we have

now there are nine places to place an (and not more than one in one place).   because we have four symbols, we need to choose four of these nine places to insert an . order does not matter because the are not distinct.

thus there are 1 · c(9,4) ways, or, if we calculate it,

thus there are 126 ways to form such "words."