Which of the following principles of experimental design reduces errors due to chance by repeating an experiment on different subjects under different conditions?

Gretchen is setting up for a banquet. she has 300 chairs and needs to distribute them evenly among t tables. how many chairs should she put at each table? write your answer as an expression.

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?

Asinusoidal function whose frequency is 1/6pi