## How do sample sizes determine accuracy? |

The materials required for this science fair project:

- 500 students age 15

- An assistant

- 5 copies of a permission letters sent to the administration of 5 different school

- 5 survey forms (one for each school)

1. For this science fair project, the independent variable is the number of students surveyed i.e.100, 200, 300, 400 and 500 students. The dependent variable is whether the students are right-handed or left-handed. This is verified by performing a simple test of dropping a pencil and observing which hand each student uses to catch it. The constants (control variables) are the age of the students and the number of students tested from each school.

2. Permission is sought from the administration of 5 schools to perform a random test on 100 students who 15 years of age. You will need to obtain the necessary permission before beginning any testing at the school.

3. When you visit the school, you should do so with your assistant. Ensure that you pre-arrange an appropriate time and venue to conduct your testing - you should enlist the help of the school administration.

4. Testing procedure: Have each student tell you their name and age. Have your assistant record these details on the survey forms. The survey forms should contain a table of 100 rows, and 3 columns. Next, a pencil is held in front of each student, whilst the student stands hand by his/her side, and he or she is asked to catch it on the count of 3. When you drop the pencil, observe which hand the student uses to catch the pencil. The observation is recorded in the form. After completing the test on all the students, the number of students that used their left hand is calculated and the results recorded in the table below. Also, the percentage of left-handers in the school is calculated. You should record the percentage of left-handers for the first 10 students tested, then the first 50, and subsequently, the first 100.

5. Procedure 4 is repeated in the remaining four schools. At the end of the experiment the results of the tests done on the previous days are added to the daily result. This is done so that the total number of students that were surveyed will accumulate from 100, 200, 300, 400 to 500 The new percentage of left-handers are calculated and recorded in the table below.

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Complexity level:

4

Project cost ($):

10

Time required:

1 hour to prepare, 5 days for observation

Material availability:

Safety concerns:

Basic safety requirements

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