500
Sally predicted that taller people were able to run faster, but wanted to check her prediction. Sally measured all of her classmates’ height in centimeters and recorded it in her chart. Each classmate then ran one mile while Sally timed them with a stopwatch and recorded the data in seconds.
How could Sally's experiment be improved?
ex: test only girls or only boys, do multiple trials, test people who are the same age, test people who have the same amount of running experience