
Survey Sample Size and Accuracy
Medium
Does surveying more people give you more accurate results? You test this by measuring left-handedness across groups of different sizes: 100, 200, 300, 400, and 500 participants.
At each school you visit, you drop a pencil in front of each person and note which hand they catch it with. Then you calculate the percentage of left-handed people in each group. Comparing those percentages as the sample grows reveals whether larger groups produce more stable results.
Hypothesis
The hypothesis is that as the number of participants increase, the results of the survey will be more accurate.
Method & Materials
You will need to obtain permission from 5 different schools to survey 500 students who are 15 years old. You will need to drop a pencil in front of each student and observe which hand they use to catch it.
You will need 500 students age 15, an assistant, 5 copies of permission letters sent to the administration of 5 different schools, and 5 survey forms.
Results
The results showed that as the sample size of the participants increased, the results became more accurate. It was observed that the percentage of left-handers increased as the sample size increased.
Why do this project?
This science project is interesting because it shows how the number of participants can affect the accuracy of the results.
Also Consider
Experiment variations to consider include surveying students to determine the number of students that wear eyeglasses, or who have had their wisdom teeth extracted.
Full project details
Additional information and source material for this project are available below.Related videos
These videos explain the science behind this project and demonstrate key concepts used in the experiment.
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