Also, the right test procedure would be something like:
1. attach cable 1, and measure it 5 times.
2. attach cable 2, and measure it 5 times.
3. attach cable 1, and measure it 5 times.
4. attach cable 2, and measure it 5 times.
5. attach cable 1, and measure it 5 times.
6. attach cable 2, and measure it 5 times.
7. attach cable 1, and measure it 5 times.
8. attach cable 2, and measure it 5 times.
9. attach cable 1, and measure it 5 times.
10. attach cable 2, and measure it 5 times.
....
19. attach cable 1, and measure it 5 times.
20. attach cable 2, and measure it 5 times.
Then calculate the mean and standard deviation of all measurement points and plot both the means curves, and means+2.3*std.dev and means-2.3*std.dev curves, and see if they overlap