Please help me quick I have a hard crossword puzzle se if you can figure it out.?

it is do for school tomorrow i need one more word here are the hints; scientists do their experimental tests more than once, so they can reduce the effects of errors. This is called conducting ___________. It is a 14 letter word, the second letter is e, the third letter is p, and the fourth letter is a. well thats all the hints please hurry and see if you can figure it out and tell me the answer by 7:30 tomorrow morning thanks so much bye.