My comments are in italic. Could you give me reasons why results from direct measurement are different from calculation for the first two questions?

How does the spring constant in series found by direct measurement compare with the spring constant found by calculation? The spring constant is 0.1675 using the red and green spring constants. However, the spring constant is 0.1794 by direct measurement.

How does the spring constant in parallel found by direct measurement compare with the spring constant found by calculation? By calculation, the spring constant in parallel in 0.7774. By direct measurement, the spring constant is 0.7447.

Explain the rule for adding springs in series with respect to the spring constant. Each spring experiences the same pull from the mass so each individual spring would extend the same amount.

Explain the rule for adding springs in parallel with respect to the spring constant. The equivalent or resultant spring constant is the sum of all spring constants of the springs.