To Investigate Length of Battery Life While Accounting for the Device

Multiple Choice

To investigate length of battery life while accounting for the device the battery lives in, an experiment is run once for each combination of brand of AAA batteries and device (TV remote, hand-held game, flashlight and digital camera) .The twelve runs are ordered randomly.The time (in minutes) that each battery lasts under continuous usage is recorded.Which of the following statements is true about this design?

A) This is a completely randomized design in one factor.
B) The devices serve as blocks to account for the variability between the lengths of time batteries last in different devices.
C) The interaction effect between brand of battery and type of device is significant.
D) This is an observational study.
E) This is a retrospective study.