How do sample sizes determine accuracy?
The hypothesis that as the number of participants increases, the results of the survey are more accurate, is correct.
Statistics is a very powerful tool that is used in science, economics, human behavior, engineering and many more applications. Businesses conduct consumer surveys regularly to collect data that can be used to analyze and predict the future expectations and demands of consumers. Independent bodies like Gallup Poll conduct political surveys to predict election results.
Try to repeat the science fair project using other surveys, for example surveys to determine the number of students that wear eyeglasses, or who have had their wisdom teeth extracted .
What if the sample size were to be increased significantly (for example, over tenfold) Do you think there will be any difference in your results? What if you were to vary your experiment, by holding the pencil near the student's right hand. Do you think you'll see any difference in your results?
Statistics - http://en.wikipedia.org/wiki/Statistics
Sample size and accuracy - http://science.jrank.org/pages/5952/Sample-Sample-size-accuracy.html
Basic safety requirements