Which of the following principles of experimental design reduces errors due
to chance by repeating an experiment on different subjects under different
conditions?
A. Placebo effect
B. Replication
C. Randomization
D. Control
E. Blindness

An automated water dispenser fills packets with one liter of water on average, with a standard deviation of 5 milliliter. the manual says that after a year of operation the dispenser should be tested to see if it needs recalibration. a year later a number of filled packets are set aside and measured separately. it is found that the average packet now contains about 0.995 liters. does the dispenser need calibration? explain your answer.

What is the perimeter of a rectangular building that is 80 feet wide and 140 feet deep?

In the diagram of circle o, what is the measure of zabc?