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### Lessons 5: Analyzing Tensile Strength Data

Tensile strength is a measure of how much pulling-apart stress a material can withstand before the material fails. Can you use a simple data analysis tool to better assess the tensile strength of various materials?

### Doing the science

- Start the Bridge Metal Simulation by clicking on the "Sim" tab.
- Click on the "Tensile Center" button.
- Click the "New Sample" icon and choose "Sample #1."
- Click once on the red-colored "Tension" lever.
- Note and record in Table 1 the number appearing on the "Tensile-o-Matic 2012 machine. This is the amount of stress in megapascals (MPa) the material withstood before failing.
- Click on "Reset" button.
- Repeat steps 4 - 6 for a total of 20 trials.
- Click the "New Sample" icon and choose "Sample #4."
- Repeat steps 4 - 6 for a total of 20 trials for Sample #4.
**Enter your Table 1 data into a spreadsheet.**- Calculate and record in Table 1 the average breaking point for Sample 1’s trials 1 – 10.
- Repeat step 11 for Sample 1’s trials 11 – 20.
- Calculate and record in Table 1 the average breaking point for Sample 4’s trials 1 – 10.
- Repeat step 13 for Sample 4’s trials 11 – 20.
- Run a Student’s t-test to compare the averages for Sample 1’s trials 1 – 10 and trials 11 -20. Record the p value in Table 1.
- Run a Student’s t-test to compare the averages for Sample 4’s trials 1 – 10 and trials 11 -20. Record the p value in Table 1.
- Run a Student’s t-test to compare the averages for Sample 1’s trials 1 – 20 and Sample 4’s trials 1 – 20. Record the p value in Table 1.