A random sample of 30 digital cameras is selected and divided into two groups. One group uses a brand- name battery while the other uses a generic plain-label battery. All variables beside battery type are controlled. Pictures are taken under identical conditions and the battery life of the two groups is compared. This is an example of an A) observational study. B) designed experiment. ere is the link to the formula sheet that you are allowed to use on this exam Math 01 FormulaSheet